Research Of Regulation Mechanism Of PI3K/Akt Pathway On Diabetic Peripheral Neuropathy Schwann Cells Secretion

Ojective: Pathogenesis of diabetic peripheral neuropathy is not fully elucidated but is known related to the reduction of neurotrophic factors synthesized and secreted by schwann cells.PI3K/Akt pathway is one of the cell signal transduction pathways and can be inhibited by diabetic peripheral neuropathy obviously.The relationship between the inhibition of schwann cells PI3K/Akt pathway and the reduction of neurotrophic factors is not reported.This research demonstrates this relationship through detecting the expression of BDNF,NGF,Akt and phosphorylated Akt of diabetes mice and in vitro schwann cells RSC96 in high-sugar environment.Methods:1.Establish animal modelSixteen male CD1 mice were randomly divided into two groups,namely the normal control group and diabetes group.Diabetic mice model was established by intraperitoneal injection of STZ.Normal control group was only injected equal volume of citrate buffer.The mice were sacrificed after sixteen weeks’ anesthesia;sciatic nerve tissue was detected for BDNF and NGF expression through western blot and immunohistochemistry.2.Insulin(PI3K/Akt pathway activator)and high-sugar treatment schwann cellsRSC96 is divided into four groups,the normal concentration of glucose group(N),the high concentration of glucose group(H),the normal concentration of glucose & insulin group(N+INS),the high concentration of glucose & insulin group(H+INS).After three days’ different stimulation,phospho-Akt(Ser473,Thr308),Akt,BDNF and NGF expression were detected through western blot and immunohistochemistry.Results:1.Expression of phospho-Akt(Ser473),BDNF and NGF decreased in sciatic nerve tissue of diabetic model miceWestern blot results of nerve tissue protein in diabetic model mice showed that compared with control group,BDNF and NGF protein decreased,Immunohistochemistry results showed that phospho-Akt(Ser473)in sciatic nerve fibre of normal mice showed yellow color,while the color was significantly lighter in diabetic mice group.BDNF and NGF in normal group showed deep brown,while the diabetic group showed an obviously lighter color,pale yellow.2.Expression of BDNF and phospho-Akt(Ser473,Thr308)proteins decreased and Akt increased in Schwann cells with high-suger instimulationWestern blot results of phospho-Akt(Ser473,Thr308)and BDNF protein,compared with group N,decreased;Akt increased.Immunohistochemistry results showed that BDNF is expressed in cytoplasm and karyon.Compared with group N,BDNF proteins of group H showed obvious lighter colors.3.Insulin treatment reversed the decreased expression of BDNF and phospho-Akt(Ser 473,Thr308)of high sugar groupWestern blot results in H+INS group showed that compared with high sugar group,BDNF and phospho-Akt(Ser473,Thr308)protein increased.Immunohistochemistry results showed that compared with high sugar group,Endonuclear BDNF proteins of H+INS group slightly increased and showed deeper colors.Conclusions:1.Content of BDNF can be reduced by high-sugar through inhibiting PI3K/Akt pathway in diabetic model mice and vitro cultured schwann cells.2.DBNF synthesis inhibition cased by high-sugar can be reversible in insulin stimulated schwann cells under high-sugar environment.