The Effects Of Insulin On RANKL In Cultured Rat Vascular Smooth Muscle Cell And Mechanism Involved

Chapter One Insulin increases the expression of RANKL in rat calcifying vascular smooth muscle cellsObjective:This part,we investigated the effects of insulin on the expression of receptor activator of NF-κB Ligand (RANKL) in rat calcifying vascular smooth muscle cells(CVSMCs).Methods:The expression of RANKL mRNA in CVSMCs was detected by RT-PCR and RANKL protein was analyzed by ELISA.Results:1.Insulin increased the expression of RANKL mRNA and protein in rat CVSMCs.2. Insulin increased the expression of mRNA in a time-dependent manner.Conclusion:Insulin increased the expression of RANKL in rat CVSMCs. Chapter Two Insulin increases the expression of RANKL in rat calcifying vascular smooth muscle cells by ERK1/2 signal pathwayObjective:In the above study,we first found insulin increased the expression of RANKL in rat CVSMCs,but the mechanism of the effect of insulin on CVSMCs was unclear.In the present study,we investigated the signal pathway by which insulin increased CVSMCs RANKL in vitro.Methods:Insulin and together with PD98059(an inhibitor of ERK1/2), LY294002 (an inhibitor of PI3K) or HIMO (an inhibitor of Akt) treated CVSMCs in vitro,p-ERK1/2,ERK1/2,p-Akt,Akt were analysed by Western Blot.Insulin and together with PD98059 (an inhibitor of ERK1/2), LY294002 (an inhibitor of PI3K) or HIMO (an inhibitor of Akt) treated CVSMCs in vitro, the expression of RANKL mRNA in rat CVSMCs was detected by RT-PCR.Results:1.Insulin induced ERK1/2 and Akt signal pathways in rat CVSMCs.2.The effect that insulin increased the expression of RANKL mRNA was blocked by pretreatment of CVSMCs with ERK inhibitor.That date suggested that ERK played an important role in increasing the expression of RANKL in rat CVSMCs.Conclusion:Insulin promoted the expression of RANKL through ERK1/2 activation, but not PI3K/Akt activation in rat CVSMCs.