The Role Of TRPC6 Through CREB In Painful Diabetic Neuropathy

Objective:Painful diabetic neuropathy(PDN)is a disease occured in diabetic patients,whose common form is diabetic mechanical allodynia(DMA).Patients with DMA can’t live normally in the long duration of diabetes mellitus(DM).However,the pathophysiology underlying of the DMA remains unclear.In this study,the purpose is to investigate the expression of Transient Receptor Potential Canonical(TRPC6)and Phosphorylated cAMP response element binding protein(p-CREB)in dorsal root ganglia(DRGs)of rats with DMA and uncover their roles in the development and maintenance of painful diabetic neuropathy.Methods:Diabetic models were induced by intraperitoneal injection of streptozotocin(STZ,a single dose of 65 mg/kg)in adult male rats,but the rats in the CON group received citrate buffer solution only.On the 14 thday,we selected the rats with the paw painful withdrawal threshold(PWT)which is measured by von-Frey filaments.The rats whose PWT decreased more than 50% of the baseline was defined as DMA group.On the 15 h day,all of the rats received a intrathecal surgery and preventive anti-infective therapy.On the 17 thday,SKF96365(65ng/kg)was given to the rats of the DMA+SKF96365 group for treatment,and the rats of the DMA+menstruum group was given with NaCl only.Blood glucose,body weight and mechanical pain threshold tests were performed on day-3,3,7,14,21 after STZ or buffer injection.In the end,we apply the methods ofquantitative real-time PCR(qRT-PCR)and Western Blot to measure the expression levels of TRPC6 and p-CREB in the L4-6 DRGs of rats.Results:(1)Before STZ injection,blood glucose,body weight and PWT have no signifeicant difference.(2)Three days after STZ injection,blood glucose of majority of rats developed a high level and their bodyweight increased slowly than the rats received citrate buffer solution only.(3)On the 14 thday,about 52% of rats in DM group performed the bilateral hind paw mechanical trigger pain(as DMA group).(4)The expression of TRPC6 and CREB(pCREB)was increased than the rats in control group.The expression of TRPC6 and CREB(pCREB)in the DMA+skf96365 group was lower than the other two groups of DMA,the expression of TRPC6 and CREB(pCREB)in the DMA group and DMA+menstruum group were same.Conclusion:Compared with the CON group,the expression of TRPC6 and CREB in the rats of DMA were up-regulated and correlated with pain.While in the rats with DMA,the expression of TRPC6 and CREB of DMA+SKF96365 group were down-regulated and the pain relieved slightly,suggesting that the TRPC6 was involved in PDN and the TRPC6 maybe playing it’s role in DMA through pCREB.