(059) Effects of a Red-Light–Controllable Nitric Oxide Donor, NORD-1, on Diabetes Mellitus-Induced Erectile Dysfunction in Rats

Abstract

Abstract Introduction Diabetes mellitus (DM) often causes erectile dysfunction (ED). Phosphodiesterase-5 inhibitor has limited effects on diabetes mellitus-induced erectile dysfunction (DMED). One contributing factor to this reduced effect is the decreased production of nitric oxide owing to neuropathy and endothelial impairment. To address this issue, we developed a red-light–controllable nitric oxide donor, NORD-1, that successfully enhanced erectile function in intact and cavernous nerve injury model rats. Objective In this study, we investigated whether NORD-1 and red-light irradiation could improve DMED in rats. Methods Seven-week-old Sprague–Dawley male rats were used. Rats in the DM and sham groups were intravenously administered streptozotocin 50 mg/kg and saline, respectively. One week after treatment, the blood glucose levels of rats in the DM group were found to be over 250 mg/dL. Five weeks after the treatment, we performed a functional study using the measurements of intracavernous pressure (ICP) under the stimulation of the cavernous nerve. The study was performed before and after NORD-1 treatment, both with and without light irradiation. Additionally, we performed an isometric tension study using corpus cavernosum from rats treated with either NORD-1 or a control compound, SiR650. Results The ICP/MAP ratio of the DM group was significantly lower than that of the sham group before and after NORD-1 treatment without light irradiation (both P<0.05). However, after NORD-1 treatment with light irradiation, the ICP/MAP ratios of the Sham and DM groups were substantially enhanced compared with that before and after NORD-1 treatment without light irradiation (all P<0.05). The ICP/MAP ratio of the DM group was similar to that of the Sham group under the normal condition before NORD-1 treatment by light irradiation. Moreover, systemic blood pressure was not affected by NORD-1 and light irradiation. In the isometric tension study, rat corpus cavernosum from rats treated with SiR650 showed no changes under red light in both the Sham and DM groups. However, the corpus cavernosum from rats treated with NORD-1 was strongly relaxed by red light in both groups. Conclusions NORD-1 and red-light irradiation could improve DMED in STZ-induced DM rats without lowering blood pressure. Disclosure No.