Effect Of Paeoniflorin On Beta-Endorphin In Hypothalamus Of Rats With Chronic Constriction Injury Of The Sciatic Nerve

Objective To observe the effect of paeoniflorin?PF?on behavior and hypothalamic beta-endorphin??-EP?in rats with chronic constriction injury of the sciatic nerve,to explore the analgesic mechanism of paeoniflorin and to provide scientific basis for the clinical application of paeoniflorin.Methods Fifty-four Specific pathogen-free male SD rats weighing 180-200g were divided into three groups?n=18?by random digital scale method:sham operation group?Sham group?,model group?CCI group?,paeoniflorin group?PF group?.Sham group only exposed but did not ligate the sciatic nerve,CCI group and PF group established rat CCI model.60mg.kg^-1.d^-1paeoniflorin was injected intraperitoneally in the PF group after modeling,Sham group and CCI group were given the same amount of saline,continuous intervention 21d.1day before modelling?T₀?,3th day after modelling?T₁?,7th day after modelling?T₂?,14th day after modelling?T₃?,21th day after modeling?T₄?,the method of mechanical withdrawal threshold?MWT?and thermal withdrawal latency?TWL?were measured in rats with pain behavior at different time points.Six rats were randomly executed in each group after T_2,T_3,T₄time-point behavioral measurement.The hypothalamus of rats was removed,the changes of?-EP content in hypothalamus of rats at different time points were assesed by enzyme linked immunosorbent assay?ELISA?in three rats,and the change of?-EP expression in hypothalamus of rats at different time points was assesed by immunofluorescence in the other three rats.Results 1.The results of MWT and TWL showed that:T₀time point,there was no significant difference in MWT and TWL between the three groups?P>0.05?;At T_1,T_2,T_3,T₄time points,compared with the Sham group,The MWT and TWL of CCI group and PF group were decreased?P<0.05?;At T₂,T₃,T₄time points,compared with the CCI group,the MWT and TWL of PF group were increased?P<0.05?.2.The results of ELISA of hypothalamic?-EP showed that:At T₂,T₃,T₄time points,compared with the Sham groups,the?-EP content of CCI group and PF group were increased?P<0.05?,compared with the CCI group,the?-EP content of PF group were increased?P<0.05?;In the Sham group,there was no significant difference in the?-EP content at T_2,T_3,T₄three time points?P>0.05?;In the CCI and PF groups,with the prolongation of time,the content of?-EP were increased gradually and reached the peak at the T₃time point,and then decreased at the T₄time point?P<0.05?.3.The results of immunofluorescence analysis of hypothalamic?-EP showed that:At T_2,T_3,T₄time points,compared with the Sham group,the?-EP expression of CCI group and PF group were increased?P<0.05?,compared with the CCI group,the?-EP expression of PF group were increased?P<0.05?;In the Sham group,there was no significant difference in?-EP expression at T_2,T_3,T₄three time points?P>0.05?;In the CCI and PF groups,with the prolongation of time,the expression of?-EP were increased gradually and reached the peak at the T₃time point,and then decreased at the T₄time point?P<0.05?.Conclusion PF can inhibit mechanical pain sensitivity and thermal pain sensitivity in rats with CCI induced neuropathic pain,PF analgesic mechanisms may be associated with increased hypothalamic?-EP levels.