JAK2 knockout improves erectile function in diabetic mice through attenuation of fibrosis and apoptosis
Li, H1; Chen, Y-W1; Pokhrel, G1; Yang, J2; Wang, T1; Wang, S-G1; Liu, J-H1
1: Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, China; 2: Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Chinai
Objective. Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway is activated in diabetes condition and may lead to fibrosis and apoptosis in many tissues. We performed this study to investigate the effect of JAK2 knockout on the diabetic erectile dysfunction in mice, both in vivo and in vitro.
Material and Method. Cre+/+-JAK2fl/fl mice were used in our study, in which the JAK2 deficiency could be induced by tamoxifen. For the in vivo study, thirty animals were divided into three groups: (1) nondiabetic control group, (2) diabetic group, and (3) diabetic JAK2-/- group. Diabetes was induced by introperitoneal injection of 60mg/kg streptozotocin for 5 consecutive days. 12 weeks later, JAK2 knockout was induced by intraperitoneal injection of 20mg/kg tamoxifen dissolved in corn oil for 4 consecutive days in diabetic JAK2-/- group. After 4 weeks, erectile function was measured by electrical stimulation of the cavernous nerve, and ratio between intracavernosal pressure (ICP) and mean systemic arterial blood pressure (MAP) was calculated. After that penis tissue was harvested. Expression of JAK2/STAT3 pathway, transforming growth factor beta 1 (TGF-β1) , phosphorylated Smad2/3 (P-Smad2/3), Smad2/3 and collagen-IV in corpus cavernosum were measured by western blot. The deposition of extracellular collagen was determined by Masson’s staining. Apoptosis was detected with TUNEL. For the in vitro study, primary cavernous smooth muscle cells (SMCs) were extracted from Cre+/+-JAK2fl/fl mice. Cells were exposed to high glucose (30mM) to mimic diabetes condition. The effect of JAK2 knockout on the reactive oxygen species (ROS) and Ca2+ level in SMCs was investigated.
Results. The ICP/MAP was reduced in diabetic mice compared with control group, but was improved by JAK2 knockout. The expression of JAK2, phosphorylated STAT3, TGF-β1, P- Smad2/3, and collagen-IV were all decreased by JAK2 knockout in diabetic mice. JAK2 knockout reduced the ratio of collagen to smooth muscle and apoptosis in corpus cavernosum. In cavernous SMCs, JAK2 knockout could attenuate the ROS and Ca2+ levels in high glucose condition.
Conclusion. JAK2/STAT3 pathway might play a role in the development of diabetic erectile dysfunction. JAK2 knockout could improve the erectile function in diabetic mice by reducing the fibrosis and apoptosis in corpus cavernosum.
Work supported by industry: no.Go Back