Mohammad-Reza Esmaili-Nejad - Graduated Student of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
Homayoon Babaei - Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran
Reza Kheirandish - Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Bahonar University of Kerman, Kerman, Iran

Objective(s):Leptin is a novel and interesting hormone for anyone trying to lose weight, but its effects on male gonad structure in longitudinal study is unknown. The present study was designed to explore morphometrical changes of mouse testicular tissue after long-term administration of leptin. Materials and Methods:Thirty healthy mature male mice were randomly assigned to either control (n=۱۵) or treatment (n=۱۵) groups. Leptin was intraperitoneally injected to the treatment group             (۰.۱ µg/۱۰۰ µl of physiological saline) once a day for ۳۰ consecutive days, and control animals received normal saline with the same volume and route. Five mice from each experimental group were sacrificed at ۱۵, ۳۰ and ۶۰ days after the beginning of treatments. Left testes were removed, weighted and then fixed in ۱۰% buffered formalin, and stained with hematoxylin and eosine for morphometrical assays. Results:Except for sertoli cell nucleus diameter, which was affected from ۳۰th day, evaluation of other morphometrical parameters such as Johnsen’s score, meiotic index, spermatogenesis, epithelial height, seminiferous tubules diameter and spermatogonial nucleus diameter revealed significant decrease from ۱۵th day after leptin administration compare to those of the control group (P<۰.۰۵). Thus, meiotic index and spermatogonial cell nucleus diameter were two parameters that were further disturbed on ۳۰th day compare to the day ۱۵ (۳.۰۹±۰.۰۳ vs. ۳.۲۳±۰.۰۳, P=۰.۰۰۶ and ۵.۵۰±۰.۰۹ vs. ۶.۰۸±۰.۱۴, P=۰.۰۰۷, respectively). Conclusion:Our results showed that long-term administration of leptin could disturb testicular tissue structure and delay spermatogenesis process.

Leptin, Meiotic index, Sertoli cell, Spermatogenesis, Spermatogonia cell