Erectile dysfunction (ED) is a major health issue among men with diabetes, and ED induced by diabetes mellitus (DMED) is particularly difficult to treat. Therefore, novel therapeutic approaches for the treatment of DMED are urgently needed. Exosomes, nanosized particles involved in many physiological and pathological processes, may become a promising tool for DMED treatment. In this study, we investigated the therapeutic effect of exosomes derived from corpus cavernosum smooth muscle cells (CCSMC‐EXOs) on erectile function in a rat model of diabetes and compared their effect with that of exosomes derived from mesenchymal stem cells (MSC‐EXOs). We incubated labelled CCSMC‐EXOs and MSC‐EXOs with CCSMCs and then observed uptake of the exosomes at different time points using laser confocal microscopy. CCSMC‐EXOs were more easily taken up by CCSMCs. The peak concentration and retention time of labelled CCSMC‐EXOs and MSC‐EXOs in the corpus cavernosum of DMED rats after intracavernous injection were compared by in vivo imaging techniques. Intracavernous injection of CCSMC‐EXOs was associated with a relatively high peak concentration and long retention time. Our data showed that CCSMC‐EXOs could improve erectile function in DMED rats. Meanwhile, CCSMC‐EXOs could exert antifibrotic effects by increasing the smooth muscle content and reducing collagen deposition. CCSMC‐EXOs also increased the expression of eNOS and nNOS, followed by increased levels of NO and cGMP. These findings initially identify the possible role of CCSMC‐EXOs in ameliorating DMED through inhibiting corporal fibrosis and modulating the NO/cGMP signalling pathway, providing a theoretical basis for a breakthrough in the treatment of DMED.

Background Management of diabetes mellitus induced-erectile dysfunction (DMED) is challenging because of its poor responses to phosphodiesterase type 5 inhibitors. Increasingly important roles of 12-lipoxygenase (12-LOX) have been proven in diabetes mellitus. Aim To investigate 12-LOX activity and therapeutic effect of its inhibitor, baicalein (BE), on DMED. Methods Intraperitoneal streptozotocin injection was used to induce type I DM, and an apomorphine test was used to evaluate erectile function. In experiment A, we assessed 12-LOX expression alteration in the corpus cavernosum (CC) of rats with DMED of different levels of severity. In experiment B, rats with DMED were intraperitoneally injected with BE for 4 weeks, and control rats were injected with vehicles. The erectile function was tested by cavernous nerve stimulation before penile tissue was harvested. We performed Western blot, immunohistochemistry, immunofluorescence, Masson trichrome staining, and enzyme-linked immunosorbent assays to measure related proteins in CC. Main Outcome Measure The main outcome measures included rectile response, histologic examination, and expression alteration of related proteins. Results 12-LOX upregulation was associated with the progression of type I DMED. After 4 weeks treatment, compared with the DMED group, the DMED + BE group showed better erectile responses to cavernous nerve stimulation. In the DMED + BE group, significantly enhanced endothelial nitric oxide synthase/nitric oxide/cyclic guanosine monophosphate pathway, reduced 12-LOX expression, and inhibited p38 mitogen-activated protein kinase/arginase II/L-arginine pathway were showed in CC relative to the DMED group. In addition, overactivated oxidative stress and fibrosis in the DMED group were both partially ameliorated in the DMED + BE group. Clinical Implications BE may be considered as an effective therapy for DMED, but needs to be verified in future human investigations. Strengths & Limitations The role of 12-LOX and its inhibitor, BE, is firstly demonstrated in rats with type I DMED. However, the experimental data are derived from animal models with without evidences from cellular-based experiments. Conclusion 12-LOX might serve as an important factor in the pathogenesis of type I DMED. BE alleviated erectile dysfunction in rats with type I DMED probably by inhibiting 12-LOX expression, ameliorating endothelial nitric oxide synthase dysfunction, as well as suppressing oxidative stress and fibrosis.

Background Oxidative stress is a significant contributor to the poor treatment efficacy on erectile dysfunction induced by diabetes mellitus (DMED). Thus, understanding the mechanism underlying oxidative stress will aid in the identification of novel therapeutic targets. Aim To define the role of Janus kinase 2 (JAK2) in mediating oxidative stress in the corpus cavernosum smooth muscle cells (CCSMCs) and to investigate the therapeutic effect of monomeric berberine (BB), which inhibits JAK2, in the pathogenesis of DMED. Methods Streptozotocin was used to establish type I diabetic rat models and apomorphine tests were conducted to determine DMED rats. Eighteen DMED rats were divided into the DMED group and the DMED+BB group, whereas another 10 age-matched rats formed the control group. CCSMCs were isolated from the corpus cavernosum of rats and were treated with the JAK2 inhibitor alpha cyanano-(3,4-hydroxyl)N-benzophenylamine (AG490) and/or BB. Outcomes Metabolic parameters; erectile function; histologic and molecular alterations. Results Erectile function was impaired and excessive oxidative stress was found in the DMED group. Excessive oxidative stress led to decreased expression level of phosphorylated endothelial nitric oxide synthase at serine 1177/endothelial nitric oxide synthase and increased expression level of Ras homolog gene family and Rho kinase 1/2. Meanwhile, the relative expression ratio of phosphorylated JAK2/JAK2 was significantly greater in the DMED group than that in the other groups. In vitro, oxidative stress was significantly reduced along with reduced intracellular calcium upon treatment with the JAK2 inhibitor, AG490. Moreover, the CCSMCs treated with BB showed changes similar to those upon treatment with AG490. In vivo experiments also confirmed that the erectile function of the DMED+BB group was improved, accompanied by decreased phosphorylated JAK2/JAK2 and decreased oxidative stress. Clinical Translation JAK2 can be used as a therapeutic target and BB can be used as a potential drug for the clinical treatment of DMED. Strengths and Limitations This study examines the promoting effect of JAK2 on oxidative stress occurrence in the corpus cavernosum and on the development of DMED in both animal experiments and cell experiments, as well evaluates the inhibitory effect of BB on JAK2 and its therapeutic effect on DMED. The main limitation of our current study is the lack of an appropriate means for activating JAK2. Conclusions JAK2 can induce DMED by enhancing oxidative stress and BB can play a role in treating DMED by inhibiting JAK2 and reducing oxidative stress. Our study provides an option and an idea for further studies on the pathogenesis and treatment of DMED.