Protective effect of melatonin against zonisamide-induced reproductive disorders in male rats

Introduction

Zonisamide (ZNS) is a modern antiepileptic drug (AED) that is distinguished from other AEDs by its unique structure and broad mechanistic profile. The pineal hormone melatonin is involved in the regulation of reproductive function, including the timing of the luteinizing hormone (LH) surge. The aim of the present work was to study the protective effect of melatonin against the potential suppression impact of ZNS on reproductive activity.

Material and methods

Ninety adult albino male rats were allocated to several groups treated with melatonin (10 mg/kg BW), ZNS (10, 20 and 50 mg/kg BW) and 10 mg/kg of melatonin plus ZNS (10, 20 or 50 mg/kg BW, respectively). Reproductive hormones (testosterone, LH and follicle-stimulating hormone (FSH)) levels were measured in animal serum. Sperm abnormalities and DNA fragmentation in testis tissues as well as expression alteration of several reproductive-related genes were analyzed.

Results

The results revealed that ZNS decreased the levels of serum free testosterone, LH, and FSH and expression of their encoding genes in male rats. In addition, ZNS treatment increased the sperm abnormalities and DNA fragmentation and inducible nitric oxide synthase (iNOS) in testis tissues as well as GABA level in liver tissues. However, melatonin supplementation inhibited the negative symptoms of ZNS in which it increased the levels of reproductive hormones and expression of their encoding genes in the ZNS-treated rats. Moreover, melatonin decreased the sperm abnormalities, DNA fragmentation, iNOS activity and GABA level in ZNS-treated rats.

Conclusions

The data obtained in this study suggest that melatonin administration confers protection against toxicity inflicted by ZNS, and support the contention that melatonin protection is achieved by its ability as a scavenger for free radicals generated by ZNS.     

Reproductive toxicity of Roundup herbicide exposure in male albino rat

The incidence of infertility in human is on the increase and the use of Roundup herbicide and presence of its residues in foodstuff is a major concern. This study therefore aim to assess the effect of Roundup on the reproductive capacity of 32 adult male albino rats randomized into 4 groups of 8 rats per group orally exposed to Roundup at 3.6 mg/kg body weight(bw), 50.4 mg/kg bw and 248.4 mg/kgbw of glyphosate concentrations for 12 weeks while the control group was given distilled water. Serum level of reproductive hormone (testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin), oxidative stress indices in the testicular tissue, epididymal sperm morphology assessment and testicular histopathology of the rats were used as a diagnostic marker of reproductive dysfunction. Significant (p < 0.05) alterations in the level of all the reproductive hormones and oxidative stress markers assayed were observed in rats exposed to Roundup. Significant reductions (p < 0.05) in sperm count, percentage motility and significant (p < 0.05) increased in abnormal sperm cells were observed in the exposed rats. Histopathologically, severe degenerative testicular architectural lesions were seen in the Roundup exposed rats. Roundup may interfere with spermatogenesis and impair fertility in male gonad.     

不同负荷运动对雄性肥胖模型小鼠性激素和精子质量的影响

BACKGROUND: Overweight and obesity can lead to a disorder of sex hormone in men. The increase in female hormone levels may inhibit the synthesis and secretion of male hormone, increase fat accumulation and form a vicious circle. Exercise can effectively reduce body fat. OBJECTIVE: To investigate the effects of different exercise loads on sex hormone and the quality of sperm in obese male mice. METHODS: Weanling male C57BL/6J mice were divided into normal control group and obesity group. Mice in the obesity group were given high fat diet for 10 weeks to establish mouse model of obesity. The amount of food and water was recorded daily. Body weight was weighed once every week. After model induction, models were assigned to obesity moderate load exercise group and obesity high load exercise group. These models did exercises for 8 weeks. Body length was measured. Body weight, abdominal fat, testis, epididymis and seminal vesicle were weighed. Sperm activity and motility were observed by the sperm counting method in the epididymis tail. Enzyme linked immunosorbent assay was used to measure serum progesterone, follicle stimulating hormone, testosterone and estradiol.  RESULTS AND CONCLUSION: Compared with the normal control group, body weight, abdominal fat weight, and lee’s index were increased (P < 0.01); the coefficient of testis and seminal vesicle were significantly decreased (P < 0.01); serum levels of luteinizing hormone, follicle stimulating hormone and testosterone were significantly decreased and estradiol level was significantly increased (P < 0.05); sperm count and activity were significantly decreased in the obesity group (P < 0.01). Compared with the obesity group, body weight, abdominal fat weight and lee’s index were significantly decreased (P < 0.05 or P < 0.01); the coefficient of testis and seminal vesicle were significantly increased in the obesity moderate load exercise group and obesity high load exercise group (P < 0.05 or P < 0.01). Serum luteinizing hormone, follicle stimulating hormone and testosterone levels were significantly increased (P < 0.05 or P < 0.01); estradiol levels were significantly decreased (P < 0.05); sperm count and activity were significantly increased (P < 0.01, P < 0.05) in the obesity moderate load exercise group. Compared with the obesity moderate load exercise group, abdominal fat weight and lee’s index were significantly reduced (P < 0.05); serum luteinizing hormone, follicle stimulating hormone, testosterone, sperm count and activity were decreased in the obesity high load exercise group (P < 0.01). These results indicate that long-term high fat diet leads to early obesity in males, inhibits the development of the reproductive gland and reproductive organs, and causes the decrease of the level of male hormone and sperm quality. Long-term moderate load exercise effectively reduces body fat, improves the inhibitory effect on male reproductive organs and glands, and relieves the negative effect of obesity on reproductive function. The effect of long-term large load exercise on reducing body fat is better than medium load exercise, but it has little effect on improving the level of male hormone in obese mice or on relieving the negative effect of obesity on reproductive function, even has a tendency to aggravate.       

Protective effect of vitamin E and selenium combination on deltamethrin-induced reproductive toxicity in male rats

The current study was performed to assess the adverse effect of deltamethrin (DLM) on reproductive organs and fertility in male rats and to evaluate the protective role of vitamin E (VE) and selenium (Se) combination in alleviating the detrimental effect of DLM on male fertility. The lethal dose 50 (LD₅₀) of DLM for male rats was estimated at 6 mg/kg bwt. Thirty male albino rats (10-weeks-old) were divided into three groups (10 rats each): Control group was injected subcutaneously with 2 ml/kg bwt saline twice weekly and was daily administered 2 ml distilled water intra-gastrically; DLM-treated group received 0.6 mg/kg bwt (1/10 LD₅₀) DLM intra-gastrically once daily; DLM + VE/Se-treated group was injected subcutaneously with 1.2 mg/kg bwt Viteselen^®15 (VE/Se) twice weekly with concurrent daily administration of 0.6 mg/kg bwt (1/10 LD₅₀) DLM intra-gastrically. The experiment was conducted for 60 consecutive days. DLM caused a significant reduction in reproductive organs weights, sperm count, sperm motility percent, alive sperm percent, serum testosterone level and testicular reduced glutathione concentration (GSH). DLM-treated group showed a significant increase in sperm abnormalities and testicular malondialdehyde (MDA) concentrations. Histopathologically, DLM caused impairments in testes, epididymes and accessory sex glands. Conversely, treatment with VE/Se combination improved the reduction in the reproductive organs weights, sperm characteristics, DLM-induced oxidative damage of testes and the histopathological alterations of reproductive organs. Results indicate that DLM exerts significant harmful effects on male reproductive system and that the concurrent administration of VE/Se partly reduced the detrimental effects of DLM on male fertility.     

Antifertility effect of calcium channel blockers on male rats: association with oxidative stress

PurposeCalcium ions are vital in many biologic processes including a variety of enzymatic reactions, activation of excitable cells, coupling of electrical activation to cellular secretion, haemostasis, bone metabolism and sperm functions. Calcium channel blockers (CCB) appear to have a reversible anti-fertility effect on male rats which does not occur through inhibition of the pituitary-gonadal axis. While the effects of CCB on male reproductive function have been investigated, less information is available regarding other reproductive indices and the underlying mechanism in the pathogenesis of male reproductive dysfunction. Therefore, the involvement of oxidative mechanisms in the adverse manifestation induced by CCB on male reproductive functions is investigated in this study.MethodsFor this purpose, lipid peroxidation; enzymatic antioxidants such as superoxide dismutase, catalase and glutathione reduced; epididymal sperm count, motility; histopathology of the testes, epididymis, seminal vesicle, prostate glands; and reproductive performance were determined.ResultsCCB administration in rats causes significant oxidative stress in the male reproductive milieu in term of increase in malondialdehyde (MDA) level and a concomitant decrease in catalase, superoxide dismutase and reduced glutathione enzyme activities in the testes. In addition, CCB treatment significantly decreased the sperm count, sperm motility, fertility index, implantation count, and litter size in this study.ConclusionThere is substantial evidence that CCB induces significant oxidative stress in the testes, which appears to be responsible for the adverse effects of decreased sperm count and motility ultimately leading to reduced fertility in rats.     

Angiotensin II in human seminal fluid

The renin-angiotensin system (RAS) and angiotensin II are important in sperm function and male fertility. Angiotensin II type I (AT1) receptors have been identified in developing and ejaculated human spermatozoa, and angiotensin can stimulate sperm motility, the acrosome reaction and binding to the zona pellucida. However, there is little information on the availability of the hormone to spermatozoa during the reproductive process. Seminal plasma and blood plasma obtained from normal and subfertile subjects was extracted, and angiotensin content was analysed by radioimmunoassay. Values obtained for blood angiotensin II were within the normal range at 16.0 +/- 3.1 pg/ml (mean +/- SEM). Values for seminal plasma were usually 3-5 fold higher, at 51.6 +/- 9.3 pg/ml (n = 34, P < 0.0001). High performance liquid chromatography analysis showed that approximately 80% of the immunoreactive angiotensin was attributable to angiotensin II itself. However, seminal plasma angiotensin II concentrations were not correlated with blood angiotensin II, sperm concentration or sperm motility. The results show that immunoreactive angiotensin from a source other than the circulation is available to spermatozoa in human ejaculates. The results are consistent with the concept that angiotensin II has an important role in male fertility.     

Diabetes mellitus- induction: Effect of different streptozotocin doses on male reproductive parameters

Diabetes mellitus (DM) is reported to be involved in male reproductive impairment, and its impact is evident in the increased prevalence of infertility. Various studies have reported that a single parenteral injection of <40?mg/kg Streptozotocin (STZ) is ineffective in ablating pancreatic β-cells and creating a rat model to investigate the effect of DM on the male reproductive system. This study therefore aims to validate these claims.Adult male Wistar rats received either a single intraperitoneal injection of STZ (30?mg/kg or 60?mg/kg) or saline (0.9%, Control). Diabetes was confirmed after 72?h if plasma glucose levels were ≥14?mmol/L. Body weight, glucose level, fluid and food intake were measured weekly. Animals were sacrificed after 8 weeks of treatment by an overdose of sodium pentobarbital (160?mg/kg body weight). The testis and epididymis were harvested and weighed prior to preparation for histological evaluation. Epididymal sperm morphology was analysed using computer aided sperm analysis (CASA). STZ60 animals presented with significantly lower body weights compared to both control and STZ30 groups. Animals in both STZ30 and STZ60 groups showed decreased normal sperm morphology compared to control. Histological evaluation of the testes showed a decrease in the number of spermatozoa in the seminiferous tubules of animals in the STZ30 and STZ60 groups compared to control. A complete absence of spermiogenesis was observed in the seminiferous tubules of STZ60 animals. These findings prove that an STZ concentration of 30?mg/kg, which is much lower than the reported 40?mg/kg, has adverse effects on the male reproductive system via its diabetogenic effect and can therefore be used to study the impact of DM on male fertility.     

High frequency of sub-optimal semen quality in an unselected population of young men

Male reproductive function seems to have deteriorated considerably during the past 4-5 decades. However, studies of the reproductive function in unselected populations have not previously been reported. As the large majority of young men in Denmark are subjected to a compulsory medical examination for military service, this provided a unique opportunity to study the reproductive function in an unbiased population. Altogether 891 young men delivered a blood sample in which reproductive hormones were measured. From 708 of these men data were also obtained on semen quality and testis size. The median sperm concentration was 41 x 10(6)/ml (mean 57.4 x 10(6)/ml). Men with ejaculation abstinence above 48 h had slightly higher sperm concentrations (median 45 x10(6)/ml, mean 63.2 x 10(6)/ml), but even in this subgroup, 21 and 43% respectively had sperm counts below 20 x 10(6)/ml and 40 x 10(6)/ml. Among men with no history of reproductive diseases and a period of abstinence above 48 h, as many as 18 and 40% respectively had concentrations below 20 and 40 x 10(6)/ml. Sperm counts were positively correlated with testis size, percentage normal spermatozoa and inhibin B, and negatively correlated with percentage immotile spermatozoa and follicle stimulating hormone. Possible causes for this high frequency of young men with suboptimal semen quality are obscure and need to be explored. Whether these findings apply for young male populations of comparable countries remains to be seen.     

Effect of inhibiting carnitine biosynthesis on male rat sexual performance

l-carnitine has a documented role as a cofactor in cellular energy metabolism and fatty acid β-oxidation pathways and it has also been considered to function in reproductive biology. We investigated whether decreasing concentrations of l-carnitine using an inhibitor of its biosynthesis, mildronate (3-(2,2,2-trimethylhydrazinium)-propionate), would influence the sexual behavior or sperm quality in male rats. Mildronate treatment induced a significant decrease in carnitine concentration and an increase in γ-butyrobetaine (GBB) concentration in both plasma and testes extracts. However, the expression of carnitine palmitoyltransferase I in testes and testosterone concentration in plasma was not changed in mildronate treated rat. Behavioral experiments demonstrated that mildronate treatment did not decrease the sexual motivation in both sexually naive and sexually experienced rats. The densities of spermatozoa in the cauda epididymis, as well as motility, were unchanged after mildronate treatment at a dose of 100 mg/kg. In conclusion, our study provides experimental evidence that mildronate induces decrease in the free carnitine concentration in rat testes, but does not decrease the sexual activity or sperm quality of male rats.     

A maternal low protein diet during pregnancy and lactation in the rat impairs male reproductive development

Nutrient restriction during pregnancy and lactation impairs growth and development. Recent studies demonstrate long-term programming of function of specific organ systems resulting from suboptimal environments during fetal life and development up to weaning. We determined effects of maternal protein restriction (50% control protein intake) during fetal development and/or lactation in rats on the reproductive system of male progeny. Rats were fed either a control 20% casein diet (C) or a restricted diet (R) of 10% casein during pregnancy. After delivery mothers received either C or R diet until weaning to provide four groups: CC, RR, CR and RC. We report findings in male offspring only. Maternal protein restriction increased maternal serum corticosterone, oestradiol and testosterone (T) concentrations at 19 days gestation. Pup birth weight was unchanged but ano-genital distance was increased by maternal protein restriction ( P < 0.05). Testicular descent was delayed 4.4 days in RR, 2.1 days in CR and 2.2 days in RC and was not related to body weight. Body weight and testis weight were reduced in RR and CR groups at all ages with the exception of CR testis weight at 270 days postnatal age (PN). At 70 days PN luteinizing hormone and T concentrations were reduced in RR, CR and RC. mRNA for P450 side chain cleavage (P450scc) was reduced in RR and CR at 21 days PN but was unchanged at 70 days PN. Fertility rate was reduced at 270 days PN in RC and sperm count in RR and RC. We conclude that maternal protein delays sexual maturation in male rats and that some effects only emerge in later life.     

The Anti-Oxidant Effects of Ginger and Cinnamon on Spermatogenesis Dys-function of Diabetes Rats

Background

Diabetes rats have been linked to reproductive dysfunction and plant medicine has been shown to be effective in its treatment. Antioxidants have distinctive effects on spermatogenesis, sperm biology and oxidative stress, and changes in anti-oxidant capacity are considered to be involved in the pathogenesis of chronic diabetes mellitus. Ginger and cinnamon are strong anti-oxidants and have been shown to reduce oxidative stress in the long-term treatment of streptozotocin (STZ)-induced diabetes in animal models. The present study examined the influence of combined ginger and cinnamon on spermatogenesis in STZ-induced diabetes in male Wistar rats.

Materials and Methods

Animals (n = 80) were allocated randomly into eight groups, 10 each: Group 1: Control rats given only 5cc Normal saline (0.9% NaCl) daily;Group2: rats received ginger (100mg/kg/rat) daily; Group 3: rats received cinnamon (75mg/kg) daily; Group 4: rats received ginger and cinnamon, (100mg/kg/rat ginger and 75mg/kg cinnamon) daily; Group 5: Diabetic control rats received only normal saline. Group 6: Diabetic rats received 100mg/kg/day ginger; Group 7: Diabetic rats received 75mg /kg/ day cinnamon; Group 8: Diabetic rats received ginger and cinnamon (100mg/kg/day and 75mg/kg /day). Diabetes was induced with 55 mg/kg, single intra-peritoneal injection of STZ in all groups. At the end of the experiment (56th day), blood samples were taken for determination of testosterone, LH,FSH, total anti-oxidant capacity, and levels of malondialdehyde, SOD, Catalase and GPX. All rats were euthanized, testes were dissected out and spermatozoa were collected from the epididymis for analysis.

Results

Sperm numbers, percentages of sperm viability and motility, and total serum testosterone increased in ginger and cinnamon and combined ginger and cinnamon treated diabetic rats compared with control groups. Serum testosterone, LH and FSH were higher compared to control group and also serum anti-oxidants (TAC, SOD, GPX and catalase) all were increased at the end of treatment. Combined ginger and cinnamon showed more intense increase in all parameters compare to ginger and cinnamon alone. Most of the results were significant (P<0.05).

Conclusion

We concluded that combined ginger and cinnamon have significant beneficial effects on the sperm viability, motility, and serum total testosterone, LH,FSH and serum anti-oxidants'' level and could be effective for maintaining healthy sperm parameters and male reproductive function in diabetics.     

男性免疫性避孕疫苗的应用研究

近年来男性免疫性避孕控制生育的研究日益增多.男性免疫避孕的理想目标是在不影响性激素水平、性欲和性功能的基础上研制出一种高效、安全、可逆的避孕疫苗,其基本原理是通过外源性靶抗原抗体中和体内生殖激素的作用,抑制精子发生,进而避孕.研究方法主要从生殖激素(GnRH、FSH、LH及其相应受体)和精子中筛选最为合适的靶抗原用于免疫避孕疫苗的研究,睾酮激素下降明显、抗体滴度小、精子不可逆抑制是目前存在的常见问题.当今选择特异结合靶点抗原以及精子相关靶抗原进行免疫性避孕的方法有效促进了男性避孕疫苗的开发,是有前景的研究重点之一.     

低剂量棉酚与激素联合应用的抗生育作用位点的研究

目的 探讨低剂量棉酚与激素联合应用在8周内使大鼠达到不育效果的作用位点.方法 本实验采用大鼠喂服棉酚12.5mg/(kg·d) 去氧孕烯125μg/(kg·d) 炔雌醇25μg/(kg·d) 十一酸睾丸酮100mg/(kg·d)的联合用药方式,与单独喂服相同剂量的棉酚或激素的大鼠及喂服载体溶剂的大鼠相对照,通过一系列形态学观察和半定量检测,探讨联合用药的具体作用环节.结果 无论在睾丸组织形态还是睾丸精子数量,联合用药组的变化趋势都与单独应用激素组的相似,而不同于单独应用棉酚组和对照组.而在附睾中,3个用药组在精子活力和精子形态方面,都与对照组有显著差异.结论 联合用药组中激素主要使睾丸精子数量迅速下降;而在精子数量大大下降的基础上,棉酚和激素又对已成熟精子的结构和运动能力进一步破坏,从而使雄性大鼠受精能力迅速下降,联合用药组比单独应用其中一种成分更快、更有效地达到使大鼠不育的目的.     

Effects of a soybean milk product on feto-neonatal development in rats

Since estrogenic pollutants and phytoestrogens can cause the disorder of the reproductive system, the effects of a soybean milk product (Vegemil? containing 162 ppm isoflavones) on the feto-neonatal development, including male reproductive function, were investigated. Pregnant rats were fed the soybean milk (5% or 100% in drinking water) from gestational day (GD) 6 to parturition or to post-natal day (PND) 56. Specifically, the rats were divided into 4 groups: the control group (drinking water), the GD5% group (5% soybean milk during only the GD period), the GDPND5% group (5% soybean milk during the GD and PND periods), and the GD-PND100% group (100% soybean milk instead of water during the GD and PND periods). During the gestational, lactational, and developmental periods, the reproductive and developmental parameters of dams and offspring were observed. Feeding soybean milk did not affect the birth and physical development of both male and female offspring. At PND57, the weights of the testes and epididymides of F1 males significantly increased by feeding a high concentration of the soybean milk (GDPND100%). In addition, feeding of the soybean milk during both the GD and PND periods (GD-PND5% and GDPND100%) enhanced the sperm counts and motility. The results indicate that soybean milk is safe for embryos, fetuses, and offspring, and improves the post-generational development of male reproductive function.     

Experimental dapsone administration induces infertility in male Wistar rats: Mechanisms and clinical implications

Dapsone (4, 4′-diaminodiphenylsulfone, DDS) is a potent anti-inflammatory and antibacterial compound which has been used in the treatment of leprosy, vasculitis and dermatitis herpetiformis, lupus erythematosus profundus and even as an antimalarial in combination with proguanil. This study investigated the effect of the administration of dapsone on the reproductive activities of male rats using in vivo and in vitro techniques. In the in vivo study, dapsone was administered orally to male Wistar rats for 5 days or 6 weeks after which their body weight, relative reproductive organ weights, sperm parameters and reproductive hormones were determined while testicular and epididymal histology were also assessed. Data were compared using analysis of variance and Students-Newman-Keuls multiple comparison test. For the in vitro study, Sertoli cells were cultured and treated with varying doses of dapsone at different durations, thereafter Sertoli cell viability and nuclei integrity were determined. Also, the genetic expressions of Glial cell line-derived neurotrophic factor (GDNF) and transferrin were assessed. The results obtained from the in vivo study showed a duration-dependent significant decrease in body and reproductive organ weights, sperm parameters and serum testosterone concentration. Testicular and epididymal histology also showed duration-dependent degenerative changes. However, all these changes were restored towards control values in the recovery experiment. The viability and deoxyribonucleic acid (DNA) integrity of the treated Sertoli cells showed dose and duration-dependent adverse effects while GDNF and transferrin showed normal genetic expressions. These results suggest that dapsone could induce male reproductive stress by affecting testicular and epididymal structure and function.     

血管内皮生长因子及其受体在大鼠附睾内精子上的表达

背景：血管内皮生长因子及其受体在男性生殖领域中占有重要地位,但其在生殖系统中表达的意义和调节机制仍不十分清楚。 目的：观察血管内皮生长因子及其受体类fms酪氨酸激酶在青春期大鼠附睾内精子上的表达定位情况。 方法：取10只青春期雄性SD大鼠双侧附睾,分离得到浓度为(30~40)×109 L-1的精子,涂片,免疫荧光法检测精子上血管内皮生长因子及其受体类fms酪氨酸激酶的表达定位情况。 结果与结论：免疫荧光结果显示,血管内皮生长因子及其受体类fms酪氨酸激酶阳性蛋白均定位于大鼠附睾精子头部的顶体、尾部的颈段、中段和主段,尾部末段和精子核未见阳性染色。提示,血管内皮生长因子及其受体类fms酪氨酸激酶可能参与了精子的成熟过程,与精子的运动能力、获能和顶体反应有关。      

Intermittent resistance exercise and obesity,considered separately or combined,impair spermatic parameters in adult male Wistar rats

Obesity and absence of physical exercise are global problems that affect concentration and sperm quality in the male reproductive system. The purpose of this study was to examine the effect of obesity and resistance training, considered separately or in association, on testicular function and reproductive capacity. Twenty pubertal male Wistar rats were distributed into four groups: control (C) and exercise (E) groups that received standard rat chow; and obese (O) and obese with exercise (OE) groups that received a high‐fat diet. All the groups received filtered water during the experimental conditions. Groups E and OE were submitted to 8 weeks of high‐intensity intermittent training. Afterwards, testes were collected for sperm count, spermatogenic kinetics, histopathology, morphometry and immunodetection of androgen receptors (AR). The vas deferens was collected for sperm morphology. The results showed that obesity increased body weight, naso‐anal length, liver and epididymal fat weight, abnormal spermatozoa and immunodetectable AR. Intermittent exercise decreased daily sperm production (DSP), sperm count and normal spermatozoa, whereas the number of tubules with immunodetectable AR increased. The combination of obesity and intermittent training led to reduced sperm count and DSP, although abnormal spermatozoa and the number of tubules with immunodetectable AR increased. Thus, in conclusion, both obesity and resistance training impaired testicular function during puberty in rats; and this type of exercise has also been shown to be detrimental to testicular physiology.     

Morphological and biochemical changes in the adult male rat reproductive system following long-term treatment with 1,2-dibromo-3-chloropropane

Adult Long-Evans male rats were treated with various dosages of pure or technical grade 1,2-dibromo-3-chloropropane (DBCP), epichlorohydrin (Epi), or allyl chloride (AC) for 1, 3, or 6 months on a daily basis. AC, which is the substrate for the production of DBCP, and Epi, which is a contaminant and/or metabolite of DBCP, had no effect on any of the parameters of the male reproductive system studied. The deleterious effects on male reproduction are therefore attributable specifically to DBCP. The effects of DBCP were dose and duration dependent. At the lowest dose (1 mg/kg) DBCP did not have any discernible effects on the male reproductive system. By 3 months of treatment at the intermediate dose of 5 mg/kg, the morphology of the testis ranged from normally appearing seminiferous tubules to ones which contained Sertoli cells only. At 6 months of treatment there was a reduction in the weights of the testes and sexual accessory glands. At the highest dose, the majority of the rats showed advanced testicular regression by 1 month of treatment. The most extreme testicular regression was observed in the 6-month treatment group. Almost all of the seminiferous tubules of all of the rats were composed of Sertoli cells only. In some of the animals, a few isolated seminiferous tubules contained an occasional spermatogonium or primary spermatocyte. Some of the Leydig cells of the rats in this group showed morphological evidence of atrophy as evidenced by the clumping of chromatin and paucity of stainable cytoplasm. This was confirmed by lower levels of intratesticular testosterone, a significant reduction in the number of luteinizing hormone (LH) receptors and increased serum levels of LH and follicle-stimulating hormone (FSH). From these results we conclude that DBCP is a specific male gonadotoxin and that the effects are not a result of contamination or metabolism. The effects appear to be a direct action at the testicular level because feedback inhibition to the pituitary gland was adversely affected.     

Tetracycline-induced reproductive toxicity in male rats: Effects of vitamin C and N-acetylcysteine

Tetracycline, a broad-spectrum antibiotic employed clinically in the treatment of bacteria infections, is known to cause a number of biochemical dysfunctions and suspected to induce testicular damage to animals and humans, but there is paucity of data on its effect and mechanism of action on the male reproductive system. The present study therefore evaluates its spermatotoxic and testicular toxicity in male rats and the chemoprotective effects of Vitamin C (Vit C) and N-acetylcysteine (NAC). Tetracycline was administered orally at the dose level of 28.6 mg/kg body weight per day in two equal divided doses (12h interval). Vit C and NAC were also administered orally to the rats at doses of 200 and 50 mg/kg body weight per day, respectively, for the 14 days of the experiment. While there was no change in the body weights of rats, tetracycline administration caused significant decrease in the relative weights of testis, epididymis and seminal vesicles (P<0.05). Administration of tetracycline caused a reduction in the epididymal sperm motility, percentage of live spermatozoa, sperm count, and an increase in abnormal sperm morphology, as well as induction of adverse histopathologic changes in the testes. While Vit C and NAC significantly mitigated the toxic effect of tetracycline on sperm parameters, the antioxidants did not improve the adverse histopathologic changes induced by antibiotic. Treatment of rats with tetracycline significantly decreased the activities of superoxide dismutase, catalase (CAT), glucose-6-phosphate dehydrogenase, glutathione-S-transferase (GST) and the levels of GSH and serum testosterone, while the activity of gamma-glutamyltranspeptidase and the formation of malondialdehyde (MDA) increased. Both Vit C and NAC significantly attenuated the toxic effects of tetracycline to the antioxidant and testicular marker enzymes as well as markers of oxidative stress. Collectively, the results suggest that therapeutic dose of tetracycline elicits spermatotoxic and testicular toxicity in male rats through induction of oxidative stress. The chemoprotective effects of Vit C and NAC during tetracycline treatment suggest that these antioxidants may find clinical application in cellular damage involving reactive oxygen species (ROS).     

Epididymis-specific pathologic disorders in rats exposed to gossypol from weaning through puberty

Previous work in our laboratory revealed that the pubertal period of reproductive development in the male rat was particularly vulnerable to gossypol exposure, with a higher frequency of round structures in the lumen of the cauda epididymidis in the treated rats. Herein, we utilized hemicastration and electron microscopy to confirm that the epididymis is a definitive target of gossypol. Although exposure to gossypol from weaning through puberty caused a significant decrease in daily sperm production, as well as in the concentration of sperm in the epididymis, serum testosterone levels and reproductive organ weights were not altered. In gossypol treated rats, sperm morphology was compromised severely, but the epithelium in testis and epididymis appeared morphologically normal. Ultrastructural examination revealed that round structures, present only in gossypol exposed males, represented: (1) principal cells exfoliated from the epididymal epithelium; (2) epididymal epithelial cell cytoplasm containing degenerating sperm; and (3) degenerating epithelial cells, consisting of vesicles and particles of different sizes, forms and densities. Taken together, the data confirm that gossypol targets the epididymis, disturbing both the structure and function of this organ, and presumably disrupts sperm maturation.