Effect of administration of nanoparticles of human chorionic gonadotropin on testicular hemodynamics, testicular volume, testicular echotexture, and circulating testosterone and nitric oxide in pubescent goat bucks under heat stress conditions

The current study investigated the effect of a single administration of human chorionic gonadotropin hormone (hCG) and its nanoparticles (NPs) on testicular hemodynamics using Doppler ultrasonography, testicular volume, testicular echotexture (PIX), and circulating testosterone and nitric oxide (NO) in pubescent goat bucks during summer months. Fifteen Baladi goats were divided into three groups (5 in each) and subjected to a single intramuscular administration of one ml of physiological saline ( control group), one ml containing 500 IU of hCG (hCG group) or one ml containing 125 IU of hCG NPs (hCG NPs group). Testicular hemodynamics assessment was done just before administration (0 h), and at 2, 4, 6, 24, and daily till 7 days after administration. Testicular volume and PIX were measured and analyzed by B-mode ultrasonography and computer analysis software. Testosterone and NO concentrations were measured using commercial kits. Results revealed significant decreases (P ˂0.05) in Doppler indices values (resistance index and pulsatility index) especially at 24 h in the hCG group (0.314 ± 0.01, 0.382 ± 0.01, respectively) compared with the hCG NPs group (0.428 ± 0.01, 0.567 ± 0.02, respectively), and the control group (0.464 ± 0.006, 0.64 ± 0.01, respectively). There were significant increases (P < 0.001) in testicular volume, PIX, testosterone, and NO concentrations in hCG NPs and hCG groups compared to the control group. There were no significant differences between the hCG NPs and hCG groups (P ˃ 0.05) in testicular volume and PIX, while testosterone significantly increased in the hCG group compared to the hCG NPs group and NO was significantly increased in the hCG NPs group compared to the hCG group. In conclusion, a single administration of hCG or its NPs improved testicular vascularization, testicular volume, and circulating testosterone and NO in pubescent goat bucks. So, hCG NPs could be recommended for improving the reproductive performance of goat bucks under heat-stress conditions.