Morphological structure of testicles under conditions of experimental gonadopathy and after the administration of cholecalciferol in comprehensive correction schemes

Morphological structure of testicles under conditions of experimental gonadopathy and after the administration of cholecalciferol in comprehensive correction schemes Marakhovskyi I. O., Korenieva Ye. M., Laryanovska Yu. B., Smolienko N. P., Belkina І. О., Velychko N. F., Chystiakova E. Ye., Misiura K. V., Bondarenko V. O. S I "V. Danilevsky Institute for Endocrine Pathology Problems of NAMS of Ukraine", Kharkiv, Ukraine

S I "V. Danilevsky Institute for Endocrine Pathology Problems of NAMS of Ukraine", Kharkiv, Ukraine The problem of male infertility is relevant and calls for a solution. The use of the D 3 vitamin in infertility treatment schemes has a potentially positive effect on reproductive health in male individuals. The present study aims to examine the effect of vitamin D 3 , administered alone or in combination with a preparation containing the extract of Tribulus terrestris on the changes in the histological picture of testicular morphology in rats with experimental gonadopathy. Male rats with modeled reproductive function pathology (Serotonin-induced gonadopathy) were divided into groups receiving correction using cholecalciferol alone or in combination with the reference drug Tribestan (Tr), which contains an extract of Tribulus terrestris. In addition to observational microscopy, morphometric evaluation of spermatogenesis was performed on sections of the testicles stained with hematoxylin and eosin. The statistical analysis was performed using the standard software package "Statistica 6.0" with the utilization of the Student's t-test and its nonparametric counterpart, the Kruskal-Wallis test for oneway analysis of variance, followed by the Mann-Whitney test. It was found that the seminiferous tubules of rats with Serotonin-induced gonadopathy are significantly reduced in size, and their tunica propria is thickened. Sertoli cells are often destructively altered, and the uniformity of their arrangement is disrupted. A decrease in the weight of the gonads, epididymis, prostate gland, and hypoandrogenization was observed as well as a decline in spermatogenesis indicators. An improvement in the morphological characteristics of the gonads was noted following the administration of vitamin D 3 in the presence of pathology. The seminiferous tubules had a normal histological structure. The germ cells were arranged in concentric rows according to their developmental stages, and the Sertoli cells appeared visually unchanged. The population of Leydig cells appeared visually more heterogeneous than in the control animals. However, occasionally seminiferous tubules with focal necrobiosis of germ cells and dystrophy of Sertoli cells, as well as a reduction in rows of germ cells, were observed. Overall, the quantitative indicators of spermatogenesis improved after the administration of vitamin D 3 compared to rats with experimental gonadopathy, although they did not reach the levels of the intact control. The administration of a combination of vitamin D 3 and Tribestan in the presence of gonadopathy resulted in a greater positive effect compared to their individual use. The microscopic condition of the testicular tissue in rats was fully recovered. The combined use of vitamin D 3 with Tribestan normalized the weight of the gonads and their appendages, significantly reduced the manifestations in the histological sections of degeneration and damage in the reproductive cells during the period of growth and differentiation, improved the relative level of androgen status in the organism and had a positive effect on spermatogenesis in the gonads. Thus, we have established that the combined use of Сholecalciferol and Tribestan for correcting experimental gonadopathy was more effective than either of the mentioned components alone. Keywords: histological structure of the testis, gonadopathy, vitamin D, cholecalciferol, spermatogenesis.

Introduction
Over 48.5 millions of couples worldwide suffer from infertility due to reproductive dysfunction [25]. After 12 months or more of regular unprotected sexual intercourse without successful conception, the male factor alone or in combination with the female factor may be the cause of infertility in at least half of all cases. According to estimates, there are over 30 million infertile men worldwide [9]. Despite the alarming prevalence, the causes of male infertility remain in a significant percentage of cases undetermined. For instance, a prospective study of 1.737 infertile patients with abnormal semen parameters revealed the etiology of infertility in only 40 % of men [22]. The lack of a definitive diagnosis is particularly common among men with oligozoospermia. Approximately 75 % of oligozoospermia patients are diagnosed with idiopathic hypofertility [22], and this condition can be caused by gonadopathy of various origins. The impairment of the gonads causes a decrease in testicular function, accompanied by or resulting in changes in the morphostructure of the male reproductive glands, it causes hypofertility and results in a deficiency in the secretion of androgens, inhibin B, anti-Mullerian hormone, and spermatogenic insufficiency [9,21].
Various correction methods are typically used in the treatment of male infertility, including hormonal and herbal remedies, cytomedines, essential amino acids, vitamins, etc [13]. However, despite significant advancements in pharmacotherapy for disorders of the reproductive glands, the issue of male infertility remains relevant and requires a solution, considering, in particular, the fact that its treatment improves the quality of life, holds high social significance, and reduces healthcare costs [17]. This prompts further research and exploration of new approaches, means, and strategies for the management of hypofertility. Recently, the use of vitamin D 3 for this purpose has been attracting the attention of researchers. Despite the prevalent occurrence of vitamin D 3 deficiency, the question of its impact on the reproductive function of the male body, specifically the morphological structure of the gonads and the germ cell formation within them, remains up for debate. The results of clinical and experimental data show that the deficiency of this vitamin-hormone negatively affects the development of testes and the process of spermatogenesis [11], determining the qualitative and quantitative parameters of the ejaculate [8,19]. There is evidence that the use of vitamin D 3 can affect sperm motility in men with asthenozoospermia and low serum levels of 25(OH)D 3 [18]. There is an increasing number of publications highlighting the importance of vitamin D in sperm maturation [1,12].
Vitamin D 3 deficiency in animals can lead to impaired maturation of seminal ducts, reduced testicular mass, and decreased sperm concentration [7], resulting in compromised reproductive ability in males.
At the same time, effective correction of gonadal morphology and testosterone levels in rats with induced aging, which leads to decreased fertility, has been reported [14]. The addition of cholecalciferol (vitamin D 3 ) to the correction of reproductive pathology using linagliptin leads to significant recovery of testicular histoarchitectonics, normalization of steroidogenesis and spermatogenesis following experimental damage to testicular tissue by cisplatin [10].
Based on the above, the aim of our study was to determine the impact of vitamin D 3 used alone or in combination with a preparation containing an extract of Tribulus terrestris, on the histological changes in the morphological structure of rat testes with experimental gonadopathy.

Materials and methods
The study involved 30 sexually mature seven-monthold rats weighing 250-350 g. The animals involved in the study were collected from the experimental vivarium SI "V.Danilevsky Institute for Endocrine Pathology Problems of the NAMS of Ukraine". The work was carried out following the national "General ethical principles of animal experimentation" (Ukraine, 2001), which are aligned with the provisions of the "European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes" (Strasbourg, 1985) [23]. The Wistar rat population was kept under standard vivarium conditions with natural lighting, a diet recommended for this species of animal, and unlimited access to water [15].
To model the pathology of reproductive function due to gonad impairment, a Serotonin model accompanied by impaired spermatogenesis was used.
The sexually active males were randomized into groups for this purpose: S-model group (animals with an experimental model of Serotonin-induced gonadal damage, gonadopathy (EGP)); S+vehicle (rats that received the vehicle (kernel oil) alongside the modeling of EGP) (for data analysis, these two groups were combined into one S group as they did not display any differences); S+vit. D 3 (animals that received vitamin D 3 orally alongside the modeling of Serotonin-induced testicular damage); S + Tribestan (Tr) (rats that received Tr as a reference drug alongside EGP); S+vit. D 3 +Tr (animals that received both drugs orally: cholecalciferol and Tr alongside the modeling of EGP). The intact males were considered the control group.
The testicular pathology was induced by subcutaneous administration of Serotonin hydrochloride (ShanDong Octagon Chemicals Limited, China), for 14 days at a dose of 3.3 mg/kg body weight [26].
The reference drug Tribestan (Tr) was administered orally at a dose of 68 mg/kg body weight three days before the start of the Serotonin hydrochloride (SH) course, during the administration of Serotonin (14 days), and for three days after the last injection of Serotonin once a day. The dosage of the drug for the research was calculated using the species conversion factor based on the human daily dose. Cholecalciferol (D 3 ) was administered following the same protocol, at a volume of 0.5 ml with a dose of 4000 IU (per os). The solutions made from kernel oil were prepared using vitamin D 3 (powder, China, batch CHG20062009, which complies with the quality standard GB 9840-2017).
At the end of the treatment period, the animals were euthanized by rapid decapitation, and their organs (testes, epididymides, ventral part of the prostate gland) were examined during autopsy to assess their condition and determine their weight.
The testes were removed and fixed in 10 % formalin for further histological investigations. According to the method described by B. A. Vartopetov and O. M. Demchenko (1975), the type of crystallization of the prostatic fluid (PF) was determined from prostatic imprints, the assessment of the "fern leaf" phenomenon allows evaluating the level of androgenic saturation in the animals' bodies [5]. To study the morphological structure, the fixed testes were dehydrated in progressively stronger alcohols and embedded in paraffin. Sections with a thickness of 6-7 μm were obtained from the paraffin blocks using a sliding microtome MS-1, which were subsequently mounted on glass slides and stained with hematoxylin and eosin. Morphometric evaluation of spermatogenesis was performed in addition to the microscopic examination of testicular sections [2,3].
The specimens were examined under the Granum L 30(03) light microscope, and microscopic images were captured using the Granum DCM 310 digital video camera.
The photographs were processed on a Pentium 2.4 GHz computer using the ToupView software.
The statistical analysis was performed using the standard software package "Statistica 6.0" with the utilization of the Student's t-test and its nonparametric counterpart, the Kruskal-Wallis test for one-way analysis of variance, followed by the Mann-Whitney test [16]. Table 1 presents data on the organ weights of males with testicular injury induced with SH before and after correction. This pathology in males (group S) caused a decrease in the absolute weight of the testes by 20 % (p<0.05), their appendages (epididymides) by 16 % (p<0.05), and the ventral part of the prostate gland by 28 % (p<0.05) compared to those in the animals of the control group. The oral administration of vitamin D3 or Tr (groups S+vit. D 3 and S+Tr) as monotherapy did not significantly alter the state of the investigated organs compared to the data of the animals in group S, indicating the continuation of the pathological process in them.

Results
The combined use of vitamin D 3 with the baseline treatment (group S+vit. D 3 +Tr) as a correction for the pathological condition induced by experimental gonadopathy (EGP) increased absolute testes weight by 21 % (р<0.05) compared to animals in group S and even its normalization (see Table 1).
It can be assumed, therefore, that the combined use of vitamin D 3 and Tr led to a reduction in the intensity of the pathological process in the testes, accompanied by the normalization of the weight of the gonads and their appendages, but did not affect the weight of the ventral part of the prostate gland. The effect of the mentioned composition on the weight of the testes, their appendages, and the prostate gland was comparable to that of the reference medication in rats.
Subsequently, the histological structure of the gonads in male rats, whose reproductive function was impaired by SH, as well as those receiving corrective therapy, was studied.
The testes of intact rats served as a general control in our studies on the effects of vitamin D 3 ( Fig. 1) [4], administered both independently and in various correction schemes for experimental reproductive disorders, their morphological structure and morphometric indicators corresponded to normal values ( Table 2).
As demonstrated by light microscopy on sections of intact rat testes, convoluted seminiferous tubules (T) were observed, cut in a transverse or oblique direction, and had an oval or round shape. The diameter of the T was normal, and the tunica propria of the T, as well as the proteinaceous and vascular membranes, were within normal limits. The wall of the seminiferous T consisted of germ cells. In the basal compartment, spermatogonia of the seminiferous epithelium were located. Among them, there are distinguishable cells with chromatin in the nucleus of condensed type, referred to as type B, and uncondensed type, known as type A. Type A spermatogonia present as both so-called "pale" (renewing) cells and "dark" (reserve) cells. Occasionally, mitosis can be observed in spermatogonia. In the intermediate compartment of the seminiferous tubule wall, spermatocytes are located. The majority of first-order spermatocytes were in the pachytene stage. In some tubules, metaphases of the first and (less frequently) second meiotic divisions, as well as anaphase of these divisions, were well evident. In the adluminal (up to 7-20 cells), along with a few fibroblasts, were observed near the blood vessels within the interstitial spaces. The nuclei were mostly round to oval in shape, relatively large in volume, well-defined, normochromic, with noticeable evenly distributed chromatin granularity, and typically contained a single nucleolus. The cytoplasm of the cells was intensely eosinophilic, with weak peripheral vacuolization in some cells, and the cell boundaries were not clearly defined. The described state of Leydig cells indicates their normal functional activity (see Fig.1). The morphometric characteristics of spermatogenesis in intact rats corresponded to the physiological norm for these animals (see Table 2).
After inducing gonadopathy by administering SH (group S) to 25 % of the rats, histological examination of the testes revealed a significant reduction in the size of seminiferous tubules, thickening, and swelling of their tunica propria. Sertoli cells were observed in the tubular wall (often with destructive changes, most of which appeared swollen, the  (1), spermatogonia (2), spermatocytes in metaphase I and II (3), and spermatids (4) can be observed (x250); c -normochromic Leydig cells in the intertubular space (x400). Hematoxylin-eosin [4].
b Table 2. The impact of vitamin D3 on quantitative indicators of spermatogenesis in Serotonin-induced testicular pathology in rats (M±m).
Notes: 1 -statistically significant differences compared to the data of the control group, p<0.05; 2 -statistically significant differences compared to the data of the S group, p<0.05; 3 -statistically significant differences compared to the data of the S+vit. D 3 group, p<0.05; 4 -statistically significant differences compared to the data of the S+Tr group, p<0.05. nuclei sharply displaced or absent altogether, the regular arrangement of these cells was disrupted, with either individual cells or clusters present) and irregularly distributed undifferentiated cells of varying number. Some tubules were filled with necrotic debris. Accumulations of remnants of dystrophic germ cells were visible in the lumen of many tubules, while individual tubules exhibited "seminiferous syncytia" or cell clusters, characterized by giant multinuclear formations mainly containing spermatids. The intercellular stroma was extensively infiltrated with proteinaceous exudate (see Fig.2, Fig.3).

Group
In the remaining 75 % of rats, a lesser degree of atrophy signs were found, and they exhibited significant variation. In the majority of those rats, the seminiferous tubules exhibited more or less preserved spermatogenic epithelium and complete destruction of the epitheliospermatogenic layer was observed only in individual tubules or within the same tubule in a patchy pattern (the germ cells present in these foci appeared as shadow cell or were in a necrobiotic state). Frequently, in the seminiferous tubules, reduction of the germ cell rows, stratification of layers, and epithelial desquamation (disorganized displacement of structural elements into the lumen of the tubule) are observed, indicating a weakening of the intercellular connections between spermatocytes and spermatids with sustentocytes (see Fig. 3). In some tubules, there is a visually reduced presence of spermatogonia (including dark type A), very rare figures of mitosis in spermatocytes. There was a decreased presence of tubules with mature spermatozoa. There is a visually increased number of tubules in which a significant amount of residual bodies was observed in the lumen (remnants of cytoplasm shed by differentiating spermatids), indicating a weakened   function of their clearance by supporting cells. Syncytia are occasionally visible (Fig. 4, Fig. 5).
The quantitative assessment of spermatogenesis in Serotonin-exposed rats revealed changes in all its characteristic parameters: reduced number of normal spermatogonia in tubules, decreased number of tubules containing second-order spermatocytes in metaphase II of maturation (meiotic stage 12), increased frequency of tubules with sloughed epithelium. As a result, there is a significant decrease in the spermatogenesis index (see Table 2). It should be noted that the scoring of each cell layer in the tubular wall was conducted only if it contained at least 7 cells.
Androgen saturation of the organism, determined by the crystallization type of the prostate gland secretion, was significantly reduced in 25 % of rats. The phenomenon of "fern leaf" was not observed in the impression of the secretion, but isolated thick coarse cross-shaped crystals were detected against a structureless mass with small areas of "remnants" of distorted crystal branches. In the remaining 75 % of animals, the pattern of "fern leaf" was observed in the impressions, but the crystal branches were shortened, and less numerous, and the angle of divergence from the stems was significantly increased, indicating a considerable decrease in the level of androgen saturation in the organism. Overall, the assessment of crystallization of the prostate gland secretion was 1.76 scores for the group (see Table 3).
In animals with EGP after administration of the Serotonin hydrochloride and kernel oil, the microscopic picture of testicular tissue, spermatogenesis indicators, and level of androgenization based on the type of crystallization of the prostate gland secretion showed practically identical characteristics to the previously presented indicators,  Yu. B., Smolienko N. P., Belkina І. О., Velychko N. F., ... including the distribution of animals according to the severity of pathology (see Fig. 6, Fig. 7, Table 3).
After the administration of D 3 i n r a t s w i t h t h e development of pathology, an improvement in the morphological picture of testicular tissue was observed. Seminiferous T were visually of normal size and had a normal histological structure. The epitheliospermatogenic layer contained germ cells arranged in concentric rows according to their developmental stages (including spermatozoa). The number of T with metaphase of the second meiotic division was increased (see Fig. 8). Sertoli cells were visually unchanged. The population of Leydig cells appeared visually more heterogeneous than in the control animals. The majority of Leydig cells were activated, as evidenced by the presence of large round normochromic nuclei with distinct nucleoli. The cytoplasm of these cells had a larger volume (see Fig. 9). However, in all animals with fully restored spermatogenesis, there were areas of focal necrobiosis of germ cells, dystrophy of supporting cells specifically in the regions of destruction (see Fig.  10), reduction of germ cell rows, layer disorganization, epithelial desquamation, and the presence of few cell clusters (see Fig.11). The severity of these impairments varied among different males within the group, but overall, they were more pronounced in animals from the EGP group, as confirmed morphometrically: the quantitative indicators of spermatogenesis improved after D 3 administration compared to rats with S-GP, although they did not reach the levels of intact control. For instance, the number of normal spermatogonia in the seminiferous tubules increased by 2.1 times. As a result, a significantly greater number of secondary spermatocytes were able to undergo division, and the number of tubules with the 12th stage of meiosis increased. The spermatogenesis index increased by 1.95 times (see Table 2). The reference drug Tr, administered following a similar scheme, exerted a sufficiently pronounced positive effect on the state of the testicular tissue in rats with EGP. In 50 % of the animals, cross-sections of the seminiferous tubules  revealed an unchanged strip of the spermatogenic epithelium, characterized by its width, organization, and completeness of the represented pool of germ cells.
In the rest of the rats, seminiferous tubules of varying number with areas of epithelial disorganization were found, reduction in rows of germ cells, and their stratification. The typical combination of different cell types was not disrupted (Fig. 12).
The areas varied in size, clearly showing a decrease in the number of spermatogonia. The nuclei of Sertoli cells acquired a rounded shape, with displaced nuclei (Fig. 13). The glandular cells varied in number, size, and nuclear status, with an increased presence of inactive forms in rats with changes (Fig.14).
The quantitative indicators of spermatogenesis after administration of Tr overall confirmed the visual assessment of the testicular tissue condition: the number of normal spermatogonia was significantly increased compared to the pathological control, there was an increased meiotic activity in the seminiferous tubules, minimal epithelial desquamation was observed, and the spermatogenesis index was increased. However, all these indicators did not reach the level of intact control (see Table 2).
The administration of a combination of vitamin D 3 and Tr on the background of EGP potentiates the positive effect of each component when used alone. In all 100 % of rats, the microscopic condition of the testicular tissue was completely restored. The size of the seminiferous tubules, the width of the epithelial spermatogenic layer, the presence of germ cells, their arrangement, and the typical combination of cell types corresponded to the norm. Seminiferous tubules with spermatogenic cells showing dystrophic changes or in a state of necrobiosis were not observed in all animals, and they were sporadic (see Fig. 15). There were no visually identifiable changes in Sertoli cells (see Fig. 16). Leydig cells and quantitative characteristics of spermatogenesis have been restored nearly to the intact level in these rats (see Table 2).
As for the level of androgen saturation in their organisms, in all rats of this group, the "fern leaf" pattern has been practically fully restored. Only small areas with contracted, reduced branching, and increased angle of departure from the main stem have remained. The evaluation of the pattern was 2.67 points (see Table 3).

Discussion
Summarizing the obtained results, the following observations can be made: long-term administration of Serotonin hydrochloride in a dose of 3 mg/kg leads to the development of gonadopathy, accompanied by a decrease in the mass of testes, their appendages, and the ventral part of the prostate gland, and the occurrence of pathological changes in the testicular tissue of rats, characterized by destructive alterations of Sertoli cells (which are responsible for nourishing the germ cells [20]), varying degrees of destruction of seminiferous tubules, dystrophy and necrobiosis of germ cells, as a result, the spermatogenesis is suppressed, including a reduction in the number of stem cells (spermatogonia), delayed differentiation of germ cells (spermatids ® spermatozoa), and a decrease in the spermatogenic index. The obtained results are supported by the literature data on the histological structure of the testes and the submicroscopic architecture of Sertoli cells after the use of Serotonin hydrochloride [6,26]. Under the influence of Serotonin hydrochloride, the number of activated hormone-producing Leydig cells decreases, as observed in our study and reported in the literature, which leads to a decrease in the androgen status of the animals' bodies, and is confirmed not only indirectly by the test of crystallization of the prostate gland secretion (see Table 3) but also by a decrease in the level of male sex hormone associated with experimental gonadopathy [4]. The administration of vitamin D 3 does not affect the mass indicators of the reproductive organs. However, in the gonads of animals in this group, the number of normal spermatogonia increases, the percentage of seminiferous tubules with exfoliated epithelium decreases compared to the pathology but does not reach the level of intact animals, while the percentage of tubules in the 12th stage of meiosis and the spermatogenesis index normalize. After the administration of cholecalciferol in EGP, the condition of Sertoli cells improves, which patently contributes to the improvement of trophic support for germ cells, resulting in reduced dystrophic and destructive manifestations in germ cells during growth and differentiation, which in turn leads to increased reserve of spermiogenesis, an elevated spermatogenesis index, and noticeable activation of hormone-producing Leydig cells, which is the most likely cause of an increase in the androgen status of the animals' bodies [6]. In terms of the positive effects on the morphological state of the testes, spermatogenesis in the gonads, and the androgen status of the organism, vitamin D 3 when administered separately, is practically equal to the reference drug Tr, and when used in combination with the investigated preparations, the effect is potentiated. Positive changes in the morphological structure of the rat testes, observed in the group receiving combined correction (S+D 3 +Tr), contribute to the increase in the level of spermatogenesis [24] and improvement of the reproductive potential of animals with Serotonin-induced gonadopathy.

Conclusion
1. Modeling testicular hypofunction using Serotonin hydrochloride leads to the development of pathological changes in the testicular tissue of rats. Histological examination of the testes reveals a significant reduction in the size of seminiferous tubules, thickening and swelling of their tunica propria. Sertoli cells are frequently destructively altered, and the uniformity of their arrangement is disrupted. The interstitial stroma is abundantly infiltrated with proteinaceous exudate. A decrease in the weight of the testes, epididymides, and prostate gland is observed compared to intact rats, along with hypoandrogenization and a decrease in all indicators of the spermatogenesis process.
2. After the administration of D 3 in the presence of pathological changes, an improvement in the morphological picture of the testicular tissue was noted. The seminiferous tubules exhibited a normal histological structure. The epitheliospermatogenic layer contained germ cells arranged in concentric rows according to their developmental stages, including spermatozoa. The number of tubules with metaphase of the second division of maturation was increased, and Sertoli cells appeared visually unchanged. The population of Leydig cells was visually more heterogeneous than in control animals. The majority of Leydig cells were activated, as indicated by the presence of large round normochromic nuclei with distinct nucleoli. However, in all animals, alongside tubules with fully restored spermatogenesis, there were also tubules showing focal necrobiosis of germ cells and Sertoli cell dystrophy, accompanied by a reduction in the germ cell rows. Overall, the quantitative indicators of spermatogenesis improved after the administration of D 3 compared to rats with experimental gonadopathy, although they did not reach the levels of the intact control. The weight of the reproductive organs did not differ from the measurements of animals with pathology.
3. The reference drug, when administered according to a similar scheme, had a pronounced positive effect on the state of the testicular tissue in rats with experimental gonadopathy. In 50 % of the animals, cross-sections of the seminiferous tubules showed an unchanged strip of spermatogenic epithelium in terms of width, organization, and completeness of the represented pool of germ cells. The quantitative parameters of spermatogenesis in the tubules increased compared to rats with pathology, and the spermatogenic index in the gonads normalized. The typical combination of different cell types remained intact. Under conditions of Serotonin-induced gonadopathy in rats, the weight of the testes and epididymides normalized, and the weight of the prostate gland was equal to that in rats with pathology.
4. The combined use of vitamin D 3 together with Tribestan in experimental Serotonin-induced gonadopathy is accompanied by the normalization of gonad and appendage weights, it reduces histological manifestations of dystrophic and destructive changes in germ cells during growth and differentiation, improves the relative level of androgen status in the body, and has a positive effect on spermatogenesis in the gonads. Correction of Serotonininduced gonadopathy with a combination of vitamin D3 and Tribestan yields better results than using either of the mentioned components alone.