Changes in Sexual Behavior of Orchidectomized Rats Under Influence of Allotransplantation of Testicular Interstitial Cell Suspension

Bilateral orchiectomy deteriorates the structure and function of seminal vesicles in a rat model

The effects of hormone levels on ejaculation are known. In addition to thyroid hormone levels, testosterone levels are also associated with ejaculation, but no consensus has been reached on this issue. Thus, we investigated the effect of decreased testosterone levels due to bilateral orchiectomy on the chemical stimulation-induced ejaculation phases in rats. Twenty-one male Wistar rats were randomized into the orchiectomy, sham, and control groups, with seven rats in each group. Bilateral orchiectomy was performed. The ejaculation parameters were evaluated 5 days after the sham and bilateral orchiectomy operations and the waiting period in the control group. The seminal vesicle (SV) phasic contraction number and increase in basal pressure amplitude were significantly lower in the orchiectomy group (6.9 ± 3.3 and 0.6 ± 0.3 mmHg) than in the sham and control groups (11.2 ± 1.7 and 1.0 ± 0.4 mmHg, and 14.5 ± 6.6 and 1.1 ± 0.2 mmHg, respectively; p = 0.016 and p = 0.03, respectively). The interval between the SV contractions was significantly longer in the orchiectomy group (166.2 ± 104.3 s) than in the sham and control groups (76.0 ± 15.5 s and 63.1 ± 31.1 s, respectively; p = 0.014 (between groups), orchiectomy vs sham p = 0.040 and orchiectomy vs control p = 0.018). The SV weights of the rats were significantly lower in the orchiectomy group (0.14 ± 0.01 g) than in the sham and control groups (0.37 ± 0.05 g and 0.48 ± 0.03 g respectively; p < 0.0001 (between groups), orchiectomy vs sham p < 0.0001 and orchiectomy vs control p < 0.0001). The groups showed no significant differences in ejaculation time, SV basal pressure, SV maximum amplitude, and bulbospongiosus muscle contraction electromyographic activity. Our results partially clarified the relationship between decreased testosterone levels and ejaculation. Decreased testosterone levels caused statistically significant changes in SV functions and affected the ejaculation emission phase.

Correcting imbalance of sex hormones by a phosphodiesterase 5 inhibitor improves copulatory dysfunction in male rats with type 2 diabetes

INTRODUCTION

Sexual dysfunction is a common complication in men with type 2 diabetes and is often refractory to treatment. This study investigated the long-term influence of the phosphodiesterase 5 inhibitor (PDE5I) tadalafil on the level of sex hormones and sexual function in male Otsuka Long-Evans Tokushima Fatty (OLETF) rats as an animal model of spontaneous type 2 diabetes.

RESEARCH DESIGN AND METHODS

We treated 36-week-old male OLETF and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats with oral tadalafil (100 µg/kg/day) for 12 weeks; sham groups received vehicle for 12 weeks. Before and after tadalafil treatment, serum levels of total and free testosterone, estradiol, luteinizing hormone (LH), follicle-stimulating hormone and proinflammatory cytokines were compared among four treatment groups. Copulatory function was examined by matching each rat to an estrous female. After completion of the experiment, total fat mass in the abdomen was measured.

RESULTS

Testosterone levels were significantly lower in OLETF versus LETO rats at 36 weeks. After 12 weeks of tadalafil treatment, levels of testosterone were significantly increased both in OLETF-tadalafil and LETO-tadalafil groups versus vehicle groups. Tadalafil decreased estradiol levels both in OLETF and LETO rats. Furthermore, tadalafil increased serum LH levels with a reduction of proinflammatory cytokines. Total fat mass was significantly lower in the OLETF-tadalafil group versus the OLETF-vehicle group. A significant suppression of copulatory behavior, that is, elongation of intromission latency was found in OLETF rats. However, tadalafil treatment for 12 weeks shortened the intromission latency.

CONCLUSION

Our results indicate that tadalafil treatment might improve copulatory disorder in the type 2 diabetic model via improvement of an imbalance in sex hormones and an increase in LH levels.

Stimulation of Spermatogenesis and Synthesis of Testosterone by Allotransplantation of Neonatal Testicular Tissue under Tunica Albuginea of Cryptorchid Testis

The abdominal type of cryptorchism was modeled on random-bred albino rats by replacing both testes from the scrotum into the abdominal cavity for 3 weeks; thereupon they were manipulated into the scrotum. In control rats, no additional surgery was performed. In experimental rats, the testicular tissue obtained from 1-2-day rat pups was transplanted under testicular tunica albuginea. Prior to orchiopexy, the weight of testes decreased by 62.5-64.1%. In 6 month after the surgery, it increased by 36.1% in the control group, whereas in experimental rats the weight of testes elevated by 123.2% and approximated the normal value. Histologically, the control group demonstrated persistent disturbance in spermatogenesis with emptiness of numerous seminiferous tubules where only Sertoli cells could be revealed and with pronounced dystrophic alterations in the spermatogenous epithelium of the partially preserved tubules where spermatogenesis was blocked at the spermatogonial level. In contrast, the transplantation region of the experimental testes exhibited formation of novel mature testicular tissue enclosed by a connective tissue capsule incorporating the seminiferous tubules with differentiated epithelium and with the clusters of Leydig cells in the stroma. In 6 month, spermatogenesis was observed in most seminiferous tubules of the host testicular tissue, which had spermatozoa in the lumens. To the moment of orchiopexy, the blood testosterone decreased by about 2.5-fold. In control group it remained diminished during entire observation period (up to 6 month), while in the experiment group its level normalized completely as early as in 2 month and remained even elevated to the end of observation period.