The effects of long-term leptin administration on morphometrical changes of mice testicular tissue.

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. Thirty healthy mature male mice were randomly assigned to either control (n=15) or treatment (n=15) groups. Leptin was intraperitoneally injected to the treatment group (0.1 µg/100 µl of physiological saline) once a day for 30 consecutive days, and control animals received normal saline with the same volume and route. Five mice from each experimental group were sacrificed at 15, 30 and 60 days after the beginning of treatments. Left testes were removed, weighted and then fixed in 10% buffered formalin, and stained with hematoxylin and eosine for morphometrical assays. Except for sertoli cell nucleus diameter, which was affected from 30(th) 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 15(th) day after leptin administration compare to those of the control group (P<0.05). Thus, meiotic index and spermatogonial cell nucleus diameter were two parameters that were further disturbed on 30(th) day compare to the day 15 (3.09±0.03 vs. 3.23±0.03, P=0.006 and 5.50±0.09 vs. 6.08±0.14, P=0.007, respectively). Our results showed that long-term administration of leptin could disturb testicular tissue structure and delay spermatogenesis process.