摘要
Objective:To determine the neuroprotective effects of apigenin against streptozotocin(STZ)-induced diabetic neuropathy(DN).Methods:To induce DN,Wistar rats(150-200 g)were administered with STZ(55 mg/kg,i.p.).Then they were randomly assigned to various groups,viz.,normal,diabetic control,insulin(10 IU/kg,s.c.),apigenin(5,10,and 20 mg/kg,p.o.),and insulin(10 IU/kg)plus apigenin(20 mg/kg,p.o.).Various behavioral,biochemical,and molecular markers[tumor necrosis factor-alpha(TNF-α),interleukin(IL)-1β,IL-6,Toll-like receptor 4(TLR4),myeloid differentiation primary response 88(MyD88),and nuclear factor erythroid 2-related factor 2(Nrf2)]were assessed.Results:Apigenin(10 and 20 mg/kg,p.o.)substantially reduced plasma glucose levels,lipid profile,aspartate transaminase,alanine transaminase,glycated hemoglobin,and neural advanced glycation end products in STZ-induced DN rats(P<0.05).After apigenin intervention,STZ-induced changes in food and water intake,body weight,urine output,allodynia,hyperalgesia,and insulin levels were markedly improved(P<0.05).Neural antioxidant enzymes(superoxide dismutase and glutathione)and Na+K+ATPase activity were also considerably elevated(P<0.05)while the level of lipid peroxidation was diminished following apigenin therapy(P<0.05).Furthermore,apigenin markedly upregulated the Nrf2 mRNA level while downregulating the mRNA expressions of TNF-αand ILs and the protein expressions of TLR4 and MyD88(P<0.05).STZ-induced histological abnormalities in the sciatic nerve were also improved by apigenin treatment.Conclusions:Apigenin exerts its neuroprotective effect by modulating the inflammatory and oxidative stress pathways via regulating the TLR4-MyD88 signaling pathway.
