Improvement of sexual behavior, sperm quantity and quality by Quercetin in streptozotocin-induced diabetic erectile dysfunction

Diabetic-induced erectile dysfunction (ED) found a common clinical problem in male diabetic patients and that has destructive effects on their sexual life. Epidemiological studies revealed that, around 75% of diabetic patients come across with major complications in their earlier age compared to normal population[1,2]. Experimental and clinical studies have established that, diabeticinduced ED has multifactorial characteristics, involving largely of vascular and neurological insults as a result of diabetic-induced metabolic inequities[3,4]. In diabetic condition boost the expression of arginase enzyme, which decreases the availability of L-arginine as substrate to reduce the synthesis of nitric oxide (NO). Moreover, denovo diacyglycerol production promotes the protein kinase C, leading to generation of reaction oxygen species (ROS). Scarano, et al.[5] reported that diabetic mellitus (DM) causes infertility by following the effects on ejaculatory process that can be enlightened through a secondary complication of DM-induced neuropathy an autonomic syndrome[6]. Such pathological condition affects Objective: To evaluate the effect of Quercetin (QT) on erectile dysfunction and oxidative stress in penile tissue of streptozotocin-induced diabetic rats. Methods: Two weeks after diabetes induction, QT was treated to normal and diabetic rats for 5 wk. Sexual behavioral parameters including mount latency, intromission latency, ejaculation latency, post-ejaculatory interval, mount frequency and intromission frequency, were observed against stimulus females. Sperm count and their motility and viability were recorded. Serum glucose and testosterone levels were estimated. In penile tissue levels of cyclic guanosine monophosphate, thiobarbituric acid reactive substances and glutathione, and enzymatic activities of superoxide dismutase and catalase were measured. Histopathological changes were evaluated in a cross-section of penile tissue. Results: Sexual behavioral ejaculation latency, post-ejaculatory interval, mount latency and intromission latency were significantly increased while mount frequency and intromission frequency were decreased in diabetic rats. Treatment with QT corrected the male sexual behavioral levels and also enhanced the inhibited sperm count, motility and viability in diabetic rats. Serum testosterone and penile cyclic guanosine monophosphate levels were significantly increased in QT treated diabetic rats compared to untreated diabetic animals. Penile oxidative stress biomarkers were corrected by the QT treatments in diabetic rats. Histopathological evaluation revealed damaged penile tissues in diabetic rats, which was protected following QT treatment. Conclusions: QT eliminated the diabetic-induced sexual impairment and showed significant antioxidant effects in penile tissue. Further experimental studies are recommended for QT therapeutically usage. Asian Pacific Journal of Reproduction 2017; 6(1): 6-12