title: S-allyl cysteine restores erectile function through inhibition of reactive oxygen species generation in diabetic rats.
abstract: Excessive production of reactive oxygen species (ROS) by an overactive nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system in penile tissue is an important mechanism of erectile dysfunction (ED). S-allyl cysteine (SAC), a bioactive component derived from garlic, was recently reported to exert versatile antioxidant properties. We hypothesized that SAC would be able to resolve diabetes-related ED by reducing ROS generation, and designed this study to investigate this possibility as well as to determine the related underlying mechanisms. A streptozotocin-induced diabetes rat model was established and used for comparative analysis of 4-week treatment regimens with insulin or SAC. The ratio of maximal intracavernous pressure (ICP) to mean arterial blood pressure (MAP) was measured to determine erectile function. Differential levels of ROS, NADPH oxidase subunits, nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signalling pathway, and apoptosis were evaluated in cavernous tissues. Max ICP/MAP was found to be markedly decreased in untreated diabetic rats; SAC, but not insulin, treatment restored the ratio to baseline (in non-diabetic untreated controls). The corpus cavernosum of untreated diabetic rats showed increased p47(phox) and p67(phox) expression, ROS production and penile apoptotic index, and decreased phospho-endothelial nitric oxide synthase (phospho-eNOS, Ser1177) expression, cGMP concentration, B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (Bax) ratio and smooth muscle cell number. SAC treatment normalized all the diabetes-induced effects, whereas insulin treatment partially normalized the alterations, but produced no effects on P47(phox) expression, penile ROS level, apoptotic index, Bcl-2/Bax ratio and smooth muscle cell number. Collectively, these data indicate that SAC treatment can restore erectile function in diabetic rats by preventing ROS formation through modulation of NADPH oxidase subunit expression. Furthermore, the poor efficacy of conventional insulin treatment for diabetic ED may be associated with an elevated level of ROS in penile tissue.
authors: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China.
authors: J
authors: J
authors: Yang
authors: T
authors: T
authors: Wang
authors: J
authors: J
authors: Yang
authors: K
authors: K
authors: Rao
authors: Y
authors: Y
authors: Zhan
authors: R-B
authors: RB
authors: Chen
authors: Z
authors: Z
authors: Liu
authors: M-C
authors: MC
authors: Li
authors: L
authors: L
authors: Zhuan
authors: G-H
authors: GH
authors: Zang
authors: S-M
authors: SM
authors: Guo
authors: H
authors: H
authors: Xu
authors: S-G
authors: SG
authors: Wang
authors: J-H
authors: JH
authors: Liu
authors: Z-Q
authors: ZQ
authors: Ye
mesh_terms: D000818:Animals; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D008297:Male; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010410:Penile Erection / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013311:Streptozocin
chemical_list: D007328:Insulin; D017382:Reactive Oxygen Species; D013311:Streptozocin; C065299:S-allylcysteine; D052250:Nitric Oxide Synthase Type III; D003545:Cysteine