Veterinary Research Forum

Abstract Sterilization in animals serves multiple purposes, such as behavior control, performance improvement, and population management. Chemical sterilization has emerged as a promising non-surgical alternative to traditional methods. This study aimed to investigate the effects of intra-testicular injection of zinc-doped carbon dots (Zn-CDs) nanoparticles as a chemical sterilant in mature rats. Twenty-five rats were randomly divided into five groups, including a control group without injection, a sham group receiving 0.50 mL distilled water, and three treatment groups administered respectively 0.50, 2.00, and 8.00 mg kg^-1 of Zn-CDs synthesized through a hydrothermal process. Following anesthesia with ketamine and xylazine, and aseptic preparation, intra-testicular injections were administered bilaterally. At 60th day post-injections, blood samples were collected to measure serum testosterone levels using chemiluminescence immunoassay. The rats were then surgically castrated to assess sperm parameters and testicular histopathology. Testicular oxidant/anti-oxidant status was also evaluated. The results revealed a dose-dependent reduction in sperm viability, membrane integrity, and motility, accompanied by increased sperm DNA damage. The highest Zn-CDs dose caused the most significant decrease in sperm concentration, as well as severe testicular tissue damage. In addition, anti-oxidant capacity, seminiferous tubules maturation, testosterone production, and spermatogenesis declined with increasing Zn-CDs concentrations in a dose-dependent manner. These findings indicate that intra-testicular injection of Zn-CDs effectively induces infertility in mature rats and holds potential as a chemical sterilization method. With further studies to evaluate safety and efficacy, this approach could be developed as a practical solution for large-scale in situ castration, offering a non-surgical alternative for over-population control programs.

Abstract Diabetes in a long period can damage the testicular tissue and impair the male fertility potential. Recently, different herbal treatments have been used for the prevention of type I diabetes and its pathological effects. Methanolic extract of Equisetum arvense has anti-oxidant and hypoglycemic properties. Thus, the current study aimed to evaluate the protective effects of Equisetum arvense methanolic extract (EE) on diabetes-induced detrimental effects in mice testicular tissue. Thirty-two adult male mice were randomly divided into four groups including control-sham, diabetic (induced by streptozotocin, 50.00 mg kg^-1 for five days), diabetic + EE 250 (250 mg kg^-1) and diabetic + EE 500 (500 mg kg^-1). After 45 days, all animals were euthanized and their testicles were dissected out and undergone histological analyses. Moreover, the serum level of testosterone was evaluated. Analyses showed that seminiferous tubules diameter, Leydig cells number per mm² of the connective tissue, Sertoli cells number per tubule, serum level of testosterone and percentage of seminiferous tubules with positive tubular differentiation, repopulation and spermiogenesis indices were significantly decreased in the diabetic group in comparison with control-sham group. The administration of EE in test groups significantly decreased the adverse effects of diabetes (especially 500 mg kg^-1). The results of this study revealed that diabetes disturbs spermatogenesis and spermiogenesis processes in mice. Meanwhile, the EE prevents diabetes-induced damages in mice testicular tissue, which may be associated with its hypoglycemic and antioxidative activities.

Abstract Testosterone is believed to play a significant role in spermatogenesis, but its contribution to the process of spermatogenesis is not completely understood. Given that extracellular matrix (ECM) facilitates differentiation of spermatogonial stem cells (SSCs) during culture, the present study was conducted to elucidate whether testosterone contribute to the permissive effect of ECM on SSCs differentiation. In experiment 1, testosterone production was measured in testicular cells cultured for 12 days on ECM or plastic (control). In experiment 2, testosterone production was assessed in testicular cells cultured on ECM or plastic (control) and exposed to different concentrations of hCG. In experiment 3, the gene expression of factors involved in testosterone production was analyzed. Testosterone concentration was lower in ECM than in the control group in experiment 1 (p < 0.05). In experiment 2, testosterone concentration was increased in response to hCG in both groups but cells cultured on ECM were more responsive to hCG than those cultured on plastic (p < 0.05). In the experiment 3, qRT-PCR revealed the inhibitory effect of ECM on the gene expression of steroidogenic acute regulatory protein (StAR) (p < 0.05). Nevertheless, the expression of LH receptor was greater in ECM-exposed than in unexposed cells (p < 0.05). In conclusion, the present study showed that inhibiting the expression of StAR, ECM could lower testosterone production by Leydig cells during in vitro culture. In addition, the results indicated that ECM could augment the responsiveness of Leydig cells to hCG through stimulating the expression of LH receptor.

Abstract Formalin is widely used in industry and in medicine (as tissue fixative and disinfectant).It contains reactive molecules which have been known for its cytotoxic effects. To evaluate the effect of formalin exposure on the testicular tissue and sperm parameter from neonatal period through physical and sexual maturity, 28 male Wister rats were assigned into two equal test and control groups. The test group was exposed to 1.5 ppm of the vapour of 10% formaldehyde in a special chamber for 2 hr per day at 20-26 ˚C and the air pressure of 760-763 atm. After 55 days, the tubular differentiation (TDI) and repopulation (RI) indexes in testicular tissue, sperm quality parameters, serum total antioxidant capacity and testosterone level were determined. The formaldehyde-exposed animals showed severe seminiferous tubules atrophy, edematous connective tissue, arrested spermatogenesis with negative TDI and RI and vascular thrombosis compared to control group. Histomorphological studies showed a high sperm mortality and abnormality associated with a remarkable decrease in sperm count. Formaldehyde-exposed animals revealed with decreased serum level of testosterone (p < 0.05) and down-regulated antioxidant status versus control group. In conclusion, the current data provide inclusive histological and biochemical information about the chronic exposure to formaldehyde with emphasizing on reproductive disorders including histological adverse effects on the testicular tissue, spermatogenesis, sperm viability, count and the abnormalities which can potentially cause infertility after sexual maturation.