Hydrogen-rich saline treated neuropathic pain in rats by increasing autophagy / 天津医药

ABSTRACT

Objective To evaluate the role of autophagy in the treatment of neuropathic pain(NP)with hydrogen-rich saline.Methods Forty adult male Sprague-Dawley rats with successful intubation were randomly divided into 5 groups(n= 8)using a random number table:the sham operation group(group S),the neuropathic pain group(group C),the hydrogen-rich saline group(group H),the autophagy inhibitor group(group M)and the hydrogen-rich saline + autophagy inhibitor group(group HM).There were 8 rats in each group.The NP model was established by chronic constriction of the sciatic nerve(CCI)in rats.The autophagy inhibitor 3-methyladenine(3-MA)was intraperitoneally injected with 30μg/kg in the group M and the group HM.The hydrogen-rich saline(0.6 mmol/L)was intraperitoneally injected with 10 mL/kg in the group H and the group HM.The other groups were intraperitoneally injected with the same amount of normal saline twice a day for 7 consecutive days.Paw withdrawal threshold to mechanical stimulation(MWT)and paw withdrawal latency to thermal stimulation(TWL)were measured at 1 day before and 1,3,5,7 and 14 days after modeling(T0-T5).After the last measurement of pain threshold,the L4-L6 segment of spinal cord was removed for determination of the expression of autophagy-related proteins microtubule-associated protein light chain 3(LC3)Ⅱ,Beclin-1 and p62 proteins by Western blot assay.The expression levels of superoxide dismutase(SOD)and malondialdehyde(MDA)in spinal cord tissue were detected.Results Compared with the group S,MWT and TWL were decreased in the group C at T2-5,the expression levels of LC3 Ⅱ,Beclin-1 and p62 were increased,SOD activity was decreased,and MDA content was increased at T5(P＜0.05).Compared with the group C,MWT and TWL were increased in the group H at T2-5,LC3 Ⅱ and Beclin-1 protein expression levels were increased,p62 protein expression levels were decreased,SOD activity was increased,and MDA content was decreased at T5(P＜0.05).MWT and TWL were decreased in the group M at T2-5,LC3 Ⅱ and Beclin-1 protein expression levels were decreased,p62 protein expression levels were increased,SOD activity was decreased,and MDA content was increased at T5(P＜0.05).Compared with the group M,MWT and TWL were increased in the group HM at T2-5,LC3 Ⅱ and Beclin-1 protein expression levels were increased,p62 protein expression levels were decreased,SOD activity was increased,and MDA content was decreased at T5(P＜0.05).Conclusion Hydrogen-rich saline can alleviate neuropathic pain and inhibit oxidative stress in spinal cord in rats,and the mechanism may be related to the increase of autophagy.