Effect of nicotinamide adenine dinucleotide phosphate oxidase 4 blocker on sciatic nerve apoptosis in diabetic neuropathy rats
Yu Ting1, Ya Bailiu1， Cheng Hongju1， Xin Qing1, Xu Fei2, Li Lei3
1Department of Physiology, 3Department of Diagnostics, Jining Medical University, Jining 272067,China； 2Department of Vascular Surgery, the First People′s Hospital of Jining， Jining 272011, China
Abstract：ObjectiveTo investigate the nicotinamide adenine dinucleotide phosphate oxidase 4 (Nox4) expression in sciatic nerve of diabetic peripheral neuropathy (DPN) rats, and the effect of VAS2870, a Nox4 blocker, on the apoptosis of the sciatic nerve of DPN rats. Methods8 weeks old male SD rats, with an average weight of （203.5±6.4）g, were developed diabetes after one time intraperitoneal injection of STZ. The other rats were intraperitoneally injected with equal volume citric acid solution as the control group (n=10). DPN model (n=20) was established in diabetic rats after 8 weeks, and DPN rats were divided into two groups by random number table method: VAS2870 group (n=10, VAS2870 1mg/kg was injected into tail vein once a day for 7 days) and DPN group (n=10, 0.9% sterile NaCl solution was injected into tail vein once a day for 7 days). The motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) of sciatic nerve were detected by PowerLab data recording and analysis system. The expressions of Nox4, caspase-3, B-cell lymphoma factor-2（Bcl-2) and Bcl-2 associated X protein（Bax) mRNA of sciatic nerve were detected by fluorescence real time quantitative PCR reaction, and the expressions of Nox4, caspase-3, Bcl-2 and Bax protein of sciatic nerve were detected by western blot assay. ResultsThe MNCV ［(41.21±7.36)m/s］ and SNCV ［(30.39±7.66)m/s］ in DPN group were lower than those in VAS2870 group ［(49.14±8.67)m/s, (38.95±6.24)m/s］, VAS2870 could alleviate the decrease of MNCV and SNCV of sciatic nerve（q=3.58， 4.53,P＜0.05）. Compared with the expression of mRNA （5.79±0.53， 6.90±0.79， 7.39±0.67） and protein （0.59±0.13， 0.45±0.14， 0.64±0.14） in control group, the expressions of Nox4 （4.72±0.42）， caspase-3 （5.02±0.43）， Bax （5.63±0.82） mRNA （q=7.02， 6.40， 7.65,all P＜0.05） and protein （0.86±0.10， 0.78±0.17， 0.95±0.13， q=7.83， 9.15， 6.87, all P＜0.05） in DPN rats were up-regulated, while the expressions of Bcl-2 mRNA （6.81±0.60， q=6.31，P＜0.05） and protein （0.44±0.12， q=6.20，P＜0.05）were down-regulated. Compared with DPN group, the expression of Nox4， caspase-3， Bax mRNA （5.31±0.44，5.71±0.60，6.41±0.95）（q=3.66，2.98，4.02，3.38,all P＜0.05） and protein （0.72±0.13， 0.60±0.18， 0.79±0.15） （q=4.24， 5.78，3.83， all P＜0.05） in VAS2870 group were down-regulated, Bcl-2 mRNA （6.29±0.47） and protein （0.56±0.12） were up-regulated （q=3.38， 2.81, all P＜0.05）, VAS2870 partially reversed the expression changes of Nox4, caspase-3, Bax, Bcl-2 mRNA and protein. ConclusionsThe expression of Nox4 is increased in the sciatic nerve of DPN rats, and the expression of caspase-3, Bax and Bcl-2 is regulated by Nox4 to promote the apoptosis of the sciatic nerve. Nox4 blocker can restore the conduction velocity of the sciatic nerve in DPN rats by reducing the apoptosis of sciatic nerve.
