Abstract
Selenium (Se) is an essential trace element and found to have important roles in maintaining normal growth and reproduction. The effect of Se on testicular steroidogenesis and testicular expression of vascular endothelial growth factor (VEGF) and nerve growth factor-beta (NGF-β) was studied in streptozotocin (STZ)- induced diabetic rats. The study included 45 male albino rats randomly divided into 3 groups; control (group I, n=15), diabetic (group II, n=15) and diabetic supplemented with Se (group III, n=15). The investigation revealed that, diabetic group (group II) had a significant decrease in Se level and testicular steroidogenesis evidenced by the decrease in testosterone and in the activities of two important enzymes synthesizing testosterone; 3-beta-hydroxysteroid dehydrogenase (3β-HSDH) and 17-beta-hydroxysteroid dehydrogenase (17β- HSDH) compared to control group (P < 0.05). In addition, there was a significant decrease in testicular tissue levels of VEGF and NGF-β in diabetic rats compared to control rats (P < 0.05). While, diabetic group supplemented with Se (group III) exhibited a significant increase in Se level, the activities of 3 β-HSDH and 17 β-HSDH and testosterone concentration compared to group II. Also, group III exhibited a significant increase in the testicular tissue levels of VEGF and NGF-β compared to group II. In addition, Se supplementation improved testicular weight, the seminiferous tubules atrophy, the germinal epithelial cells lining tubules, Sertoli cells and interstitial cell of Leydig. In conclusion, Se supplementation increases testicular steroidogenesis and the expression of VEGF and NGF-β in STZ-induced diabetic rats.