Effect of Letrozole Administration as a Selective Aromatase Inhibitor on Male Rat's Reproductive Performance.

This study was designed to investigate the effect of administrating a selective aromatase inhibitor, letrozole, on the parameters of the rat's sperm and testicular histomorphology. A total of 40 male Wistar rats with an age of about 5 months old and an average weight of 190±10 g were divided randomly into 4 groups (n=10 each) and treated for 6 weeks. The first group (C) was given normal saline only as a control group. The second (T1), third (T2), and fourth (T3) groups received doses of 0.5, 1, and 1.5 mg/animal letrozole, respectively. At the end of the experiment (42 days), all animals were euthanized and the samples were obtained for more evolutions. The results of this study showed a significant increase in sperms quality (P-value≤0.05) while indicating a significant decrease in sperm abnormality in the T1 group, compared to the C group. Moreover, there was a significant difference represented by an increase in sperm quality, and a significant difference represented by a decrease in sperms abnormality in the T2 group, compared to the C group. On the other hand, there was a significant difference represented by an increase in sperm quality, and a significant difference represented by a decrease in sperm abnormality in the T3 group, compared to the T2 group. Normal somniferous tubules with high spermatoscopy counts were shown in histologic sections in the control group, primary and secondary spermatocytes with spermatozoa. In the T1 group, there was adequate spermatogenesis with a thick basement membrane. In the T2 group, there was normal testicular tissue with a significant increase in spermatogenic activity and number. In the T3 group, there was no significant atrophy or other pathology. The results of the current study suggested that letrozole improved spermatogenesis while causing no visible pathological alterations in testis tissue.