Leptin-induced changes in the male reproductive system: role of AMPK pathway and effects of Profortil / Ifrah Alam Malik

Excessive levels of leptin have a detrimental effect on the male reproductive system eventually leading to infertility. However, is still unclear how these effects are brought about. Several different signaling pathways are involved in mediating leptin's effects. One of these pathways is the AMPK pathway. Therefore, to understand if the AMPK pathway is involved in mediating leptin's adverse effects, Dorsomorphin was used to inhibit the AMPK pathway and observe if that would lead to any decrease or inhibition of the effects of leptin on sperm and testicular tissue in Sprague-Dawley rats. Furthermore, leptin causes these adverse effects by inducing oxidative stress. Therefore, Profortil®, a concoction of several different antioxidants, was administered to leptin­ treated rats to observe if it could prevent the adverse effects of leptin in the male reproductive system of Sprague-Dawley rats. In study I, adult male Sprague-Dawley rats were divided into three groups: Control, which was given O.lml normal saline. Leptin, which was treated with 60µg/kg/day ofleptin, and leptin+Dorsomorphin which was concurrently treated with leptin and Dorsomorphin at 5mg/kg/day. Treatments were given for 2 weeks via the intraperitoneal route. Food intake and body weight of the rats was measured weekly. At the end of the treatment, the rats were euthanized, and testes and epididymides were collected to measure the organ weight, total sperm count, percentage of sperm with abnormal morphology, ST diameter and epithelial height, expression of connexin-43 and occludin, concentration of 8-OHdG, testosterone, inhibin B, Acetyl-CcA carboxylase and phosphorylated AMPK. In study II, adult Sprague-Dawley rats were divided into 4 groups: Control, which was given O. lrnl normal saline. Leptin, which was administered 60µg/kg/day leptin for 2 weeks. Leptin+Profortil, which was given leptin and Profortil at 50 mg/kg/day. Profortil was given initially for 1 week, followed by another two weeks concurrently with leptin. The last group received only Profortil at 50mg/kg/day for 3 weeks. Normal saline and leptin were given via the intraperitoneal route. Profortil was given by oral gavage. Food intake and body weight of the rats was measured weekly. At the end of the treatment, sperm and testes were collected to measure the organ weight, total sperm count, percentage of sperm with abnormal morphology, concentration of testosterone, CYPl 7al, CYP19al, 17β-HSD, total antioxidant capacity, 8-OHdG, SOD and catalase activity, gene expression of catalase, concentration of phosphorylated AKT and PIP3, testicular cell apoptosis and sperm DNA fragmentation. Results from study I showed that leptin administration caused a decrease in total sperm count, increase in percentage of sperm with abnormal morphology, decrease in ST epithelial height, increase in concentration of 8-0HdG and decrease in gene expression of occludin and connexin-43 in the testicular tissue. Dorsomorphin administration in the leptin-induced rats did not have any significant effect on any of the parameters that were affected by leptin administration. In study II, leptin administration caused a decrease in total sperm count, increase in fraction of sperm with abnormal morphology, increased 8-OHdG concentration, decrease in catalase activity and gene expression, decreased gene expression of connexin-43 and occludin, increased testicular cell apoptosis and sperm DNA fragmentation. Treatment with Profortil prevented the effect ofleptin on the total sperm count. However, no other effects of Profortil were observed on the rest of the leptin-induced parameters measured. The results from study I indicate that perhaps the AMPK pathway may not be involved in mediating the adverse effects of leptin on the sperm and testes in the Sprague-Dawley rats. The results from study II indicate that Profortil administration was able to alleviate some effects of leptin on the male reproductive system but not all.