Effects of a single dose of long-acting FSH on testicular blood flow, testicular echotexture, and circulating testosterone, estradiol, and nitric oxide in rams during the non-breeding season

The present study investigated the effect of a single administration of long-acting follicle simulation hormone (FSH) on testicular blood perfusion as measured by pulsed-wave Doppler ultrasonography, testicular echotexture, and circulating testosterone (T), estradiol (E2), and nitric oxide (NO) in the plasma of rams in the non-breeding season. Twelve Ossimi rams were subjected to either a single administration of long-acting FSH subcutaneously (FSH group; n = 6) or the vehicle (control group; n = 6). Assessment of testicular hemodynamics at the level of the supratesticular artery was performed just before administration (0 h), and at 4, 24, 48, 72, 96, and 168 h after FSH or the vehicle administrations. Testicular volume (TV), and echotexture of testicular parenchyma including pixel intensity and heterogeneity were derived by the computer analysis software. Concentrations of T, E2, and NO were measured using commercial kits. Results revealed significant decreases (P ˂ 0.05) in the values of Doppler indices (resistive index: RI and pulsatility index: PI), especially at 48 h after administration of FSH (RI: 0.42 ± 0.02, PI: 0.56 ± 0.04) compared to their values in the control group (RI: 0.54 ± 0.03, PI: 0.77 ± 0.04). FSH administration induced significant decreases (P ˂ 0.05) in the pixel intensity of testicular parenchyma. Testicular volume and T concentrations were not significantly changed (P ˃ 0.05). Concentrations of E2 increased significantly (P ˂ 0.05) at 48 h and 72 h after FSH administration. (30.07 ± 5.23 pg/ml, 29.93 ± 1.44 pg/ml, respectively) compared to their values before FSH administration (14.63 ± 1.37 pg/ml). Concentrations of NO increased significantly (P ˂ 0.05) in the FSH group between 4 h to 48 h compared to the values in the control one. In conclusion, a single administration of long-acting FSH enhanced testicular blood perfusion as measured by pulsed Doppler ultrasonography in rams during the non-breeding season. Concurrently, significant increases in the concentrations of E2 and NO were found.

Effects of silencing epididymal vascular endothelial growth factor (VEGF) expression on hyaluronidase (HYD) activity in arsenic poisoning rats through downregulating VEGF receptor 2 (VEGFR2)

RNA interference (RNAi) was used to investigate the role of epididymal vascular endothelial growth factor (VEGF) gene expression on sperm hyaluronidase (HYD) in a rat model of arsenic poisoning and to identify a new gene therapy target for male infertility caused by arsenic poisoning. The Rat model of chronic arsenic poisoning was established. And we found that positive expression of VEGF and VEGF receptor 2 (VEGFR2) was observed by Immunohistochemical staining in the epididymal tissues of arsenic-exposed rats. Subsequently, VEGF-shRNA-1, VEGF-shRNA-2 and VEGF shRNA-3 expression vectors containing epididymal VEGF-shRNA lentivirus were constructed and injected into the bilateral epididymis of each group of rats (Control group, NC-shRNA negative infection group, VEGF-shRNA-1 group, VEGF-shRNA-2 group, VEGF-shRNA-3 group) (n = 10 per group). Compared with the negative infection group and the normal control group, the expression of VEGF and VEGFR2 mRNA and protein levels were significantly decreased following epididymal infection. In addition, the HYD activity was all significantly lower than that in the normal control group and the negative infection group. Taken together, epididymal VEGF gene silencing may inhibit the activity of sperm HYD through downregulating VEGFR2.

The relationship between vascular endothelial growth factor and spermatogenesis disturbance in an experimentally-induced unilateral cryptorchidism murine model

This study is to explore the relationship between vascular endothelial growth factor (VEGF) and pathological changes in cryptorchidism by using murine model of intraperitoneal cryptorchidism with surgical operation. To investigate the relationship between the changes of VEGF expression and heat stress inducing germ cell damage in testicular tissue. Six-week-old ICR male mice were operated to make unilateral cryptorchidism mouse model. Here in our study, a remarkable damaged of germ cells are seen in murine model of unilateral cryptorchidism. And the expression of VEGF was significantly changed in a time dependent way and consistent with the pathological changes of testis, this leading us to conclude that there was a negative correlation between VEGF levels and germ cell damage in unilateral cryptorchidism mouse model. We propose that there is a time dependent decrease of VEGF expression in cryptorchidism and confirm that VEGF is essential in spermatogenesis disorder caused by cryptorchidism and non-obstructive azoospermia.

Effect of a single injection of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on testicular blood flow measured by color doppler ultrasonography in male Shiba goats

Although color Doppler ultrasonography has been used to evaluate testicular blood flow in many species, very little has been done in goat. Eight male Shiba goats were exposed to a single intramuscular injection of either gonadotropin-releasing hormone (GnRH group; 1 µg/kg BW) or human chorionic gonadotropin (hCG group; 25 IU/kg BW). Plasma testosterone (T), estradiol (E2) and inhibin (INH) were measured just before (0 hr) and at different intervals post injection by radioimmunoassay. Testis volume (TV) and Doppler indices, such as resistive index (RI) and pulsatility index (PI) of the supratesticular artery, were measured by B-mode and color Doppler ultrasonography, respectively. The results indicated an increase in testicular blood flow in both groups, as RI and PI decreased significantly (P<0.05), but this increase was significant higher and earlier in hCG group (1 hr) than in the GnRH group (2 hr). A high correlation was found for RI and PI with both T (RI, r= −0.862; PI, r= −0.707) and INH in the GnRH group (RI, r=0.661; PI, r=0.701). However, a significant (P<0.05) correlation was found between E2 and both RI (r= −0.610) and PI (r= −0.763) in hCG group. In addition, TV significantly increased and was highly correlated with RI in both groups (GnRH, r= −0.718; hCG, r= −0.779). In conclusion, hCG and GnRH may improve testicular blood flow and TV in Shiba goats.

Spermatogenesis and cryptorchidism

Cryptorchidism represents the most common endocrine disease in boys, with infertility more frequently observed in bilateral forms. It is also known that undescended testes, if untreated, lead to an increased risk of testicular tumors, usually seminomas, arising from mutant germ cells. In normal testes, germ cell development is an active process starting in the first months of life when the neonatal gonocytes transform into adult dark (AD) spermatogonia. These cells are now thought to be the stem cells useful to support spermatogenesis. Several researches suggest that AD spermatogonia form between 3 and 9 months of age. Not all the neonatal gonocytes transform into AD spermatogonia; indeed, the residual gonocytes undergo involution by apoptosis. In the undescended testes, these transformations are inhibited leading to a deficient pool of stem cells for post pubertal spermatogenesis. Early surgical intervention in infancy may allow the normal development of stem cells for spermatogenesis. Moreover, it is very interesting to note that intra-tubular carcinoma in situ in the second and third decades have enzymatic markers similar to neonatal gonocytes suggesting that these cells fail transformation into AD spermatogonia and likely generate testicular cancer (TC) in cryptorchid men. Orchidopexy between 6 and 12 months of age is recommended to maximize the future fertility potential and decrease the TC risk in adulthood.