Role of Irisin Administration in Modulating Testicular Function in Adult Obese Albino Rats

Abstract
Background: Irisin, exercise-induced myokine, is known to improve obesity-induced metabolic disturbances by enhanc-ing thermogenesis and increasing energy expenditure. Recent studies have reported that irisin promoted cell proliferation and protected cells from apoptosis. However, the effects of irisin on testicular function in obese rats is still to be investi-gated.
Aim of the Study: This study was designed to explore the probable effects of irisin treatment on modulating the adverse effects of obesity on testicular functions with a trial to clarify some of the possible underlying mechanisms.
Material and Methods: Thirty adult male wistar albino rats (200±30g) were divided equally into 3 groups, group (I): Saline-vehicle treated normal fed group, group (II): Saline-vehicle treated rats were fed a High Fat Diet (HFD) for 10 weeks. Group (III): Irisin treated HFD-fed rats for 10 weeks and irisin was injected subcutaneously (150ml daily for 4 weeks). Rats were weighed and serum levels of glucose, insulin, lipid profile, FSH, LH, estradiol & testosterone levels, epididymal sperm count and motility, testicular Malondiald-hyde (MDA) level, Superoxide Dismutase (SOD), Catalase (CAT), Glutathione Peroxidase (GPX) activities, testicular and epidydimal fat weights were estimated. Testicular his-topathological study was done as well.
Results: There was a significant increase in the Body Mass Index (BMI) together with deterioration of metabolic, gonadal functions and testicular oxidant/antio-oxidant system in group (II), while exogenous irisin administration in group (III) resulted in: Significant decrease in BMI, insulin resistance with improvement in lipid profile, significant increase in serum FSH, LH & testosterone, sperm count and motility in male rats. Together with marked improvement in the testicular histoarchitecture. Additionally, there was a significant increase in testicular SOD, CAT & GPX activities. However, it signif-icantly decreased testicular MDA level.
Conclusions: It could be suggested that irisin has a po-tential positive role against obesity-induced testicular dys-function, which may be due to its role in maintenance of glucose & insulin homeostasis, its antioxidant properties and/ or maintenance of gonadal hormonal function via indirect and/or direct effects on the gonads.