Role Of Notchl1 Modulating PTEN/Akt/mTOR Signaling Pathway In The Pathogenesis Of Diabetic Peripheral Neuropathy

Objective:By using Notch1 signaling pathway blocker ?-secreta se inhibitor(3,5-difluorophenylacetyl)-L-alanyl-L-2-phenylglycine tertbutyl ester [(3,5-Difluorophenacetyl)-L-alanyl-S-phenylglycine-2-butyl Ester,DAPT] intervenes in diabetic peripheral neuropathy(DPN)rat s,observe and compare the weight,blood glucose,sciatic nerve con duction velocity,and plantar heat Pain threshold,sciatic nerve morp hology changes and the expression of Notch1,PTEN,Akt,and mT OR clarify the mechanism of Notch1 in the pathogenesis of DPN.Methods:(1)Twenty-four male SD rats of 6 weeks old,weighi ng 200-220 g,were randomly divided into 3 groups of 8 rats: contr ol group,diabetic peripheral neuropathy group(DPN group),diabeti c peripheral neuropathy+DAPT group(DPN+DAPT group).(2)After20 hours of fasting,rats were given a one-time 65mg/kg intraperiton eal injection of streptozotocin(STZ)for modelling.(3)Observe the changes in the general condition,blood glucose,body weight,sciati c nerve conduction velocity,and plantar heat pain threshold of rats at 1,4,and 8 weeks after administration,respectively.(4)Immunofl uorescence(IF)was used to detect the effect of DAPT on theexpre ssion of Notch1,PTEN,Akt,and mTOR in rat sciatic nerve.Results:(1)The STZ-induced diabetic rat model verifies the successful modeling:(1)Measure the blood glucose of rats: Compared wit h the control rats,the blood glucose levels of the DPN group and DPN+DAPT group were significantly increased(P<0.01),DPN+DA PT group compared with DPN group,blood glucose significantly de creased(P<0.05);(2)measured rat sciatic nerve conduction velocity:compared with control group rats,DPN group,DPN+DAPT group r at sciatic nerve conduction velocity decreased significantly(P<0.01);compared with the DPN group,the sciatic nerve conduction velocit y of the DPN+DAPT group increased significantly(P<0.01).(3)Mea suring the plantar heat pain threshold of rats: Compared with the c ontrol group,the plantar heat pain threshold of the DPN group and DPN+DAPT group was significantly increased(P<0.01).Comparedwit h the rats in the DPN group,the threshold of plantar heat pain in the DPN+DAPT group decreased significantly(P<0.01).(4)Toluidine blue staining showed that the control group had full myelin nerve f ibers and even thickness of the myelin sheath;the DPN grouphad u neven distribution of myelin nerve fibers,reduced fiber nerve diame ter,loose and disordered structure,and uneven thickness of the mye lin sheath,compared with the control group The proportion of myel in sheath in lesions increased significantly(P<0.0001);the myelin s heath morphology in the DPN+DAPT group was between thecontrol group and the DPN group,and the proportion of myelinsheath in lesions decreased significantly(P<0.05),which was significantly impr oved over the DPN group.(2)The expression of Notch1 in sciatic n erve of DPN rats was significantly increased(P<0.01);the expressi on of Notch1 in DPN+DAPT group was significantly lower than th at of DPN group(P<0.01).(3)Compared with the control group,th e expression of Akt1 and mTOR in the DPN group increased signif icantly,while the expression of PTEN decreased significantly(P<0.05);compared with the DPN group,the expression of Akt1 and mT OR in the DPN+DAPT group were significantly reduced,And the e xpression of PTEN increased significantly(P<0.05).Conclusion: Notch1 may regulate the pathogenesis of DPN rats by activating PTEN/Akt/mTOR signaling pathway.