Rapid-Onset Mechanism On β-endorphin Of Depressive Model Rat By Electro-Acupuncture

Objective:Observe the changes of depressive model rat on behavior,andβ-endorphin content both in hypothalamus and serum when treated by electro-acupuncture;explore the rapid-onset mechanism onβ-endorphin of depression after electro-acupuncture treatment.Method:70 adult male SD rats,weight (180-220g),were randomly divided into normal group,model control group,drug group,and electro-acupuncture (EA) group.Depressive model rats were replicated by isolated raised and chronic unpredicatable mild stress induction.The normal group:untreated.The model control group:use 0.9% NS filled the stomach.Drug group: the preparation with 100ml/kg solution was filled into the stomach,using 1.8mg/kg fluoxetine tablets dissolved in NS.EA group:select 2Hz acupuncture "Baihui","Yin-Tang" points,while using NS filled the stomach,1 day for 7 days. After 7 days of treatment,the rats were measured with body weight,behavior (horizontal and vertical movement) and sugar consumption.In addition,enzyme-linked immunosorbent (ELISA) was used to measureβ-endorphin content in the rat hypothalamus and plasma,and immunohistochemistry was used to measureμreceptor levels in the hypothalamic arcuate nucleus.Result:1.Comparison with body weight of rats in each group:the model group was significantly lower than normal group(P<0.01). After 7 days treatment,the weight of rats had all increased in model group,drug group and EA group.But each group was lower than normal group (P<0.01).2.Comparison with sugar consumption of rats in each group:the model group was significantly lower than normal group(P<0.01). After 7 days treatment,sugar consumption of rats in EA group increased significantly(P<0.01),higher than the drug group(P<0.05),but didn't reach normal levels(P<0.05).3.Comparison with behavior score of rats in each group:Both horizontal and vertical score were lower than the normal group(P<0.05,P<0.01).After 7 days treatment,horizontal score of rats in EA group increased significantly(P<0.01),higher than the drug group(P<0.01),almost equal to the normal level(P>0.05).However,model group.drug group and EA group were no difference in vertical score(P>0.05). 4.At the depression model rat,β-endorphin content in the plasma declined sig-nificantly(P<0.01). After 7 days treatment,the serum P-endorphin content both in drug group and EA group increased (P<0.01).EA group was higher than the drug group(P<0.05),but didn't reach normal levels(P<0.01).5. On the rat model of depression,β-endorphin content in the rat hypothalamus,and average optical densityofμreceptor in the hypothalamic arcuate nucleus also decreased(P<0.01).After7 days treatment,β-endorphin levels continued to drop at hypothalamus both in drug group and EA group.The EA group decreased significantly (P<0.01),lower than the drug group (P <0.05).While the verage optical densityofμreceptor in the hypothalamic arcuate nucleus increased significantly(P<0.01),EA group was higher than the drug group(P<0.01),but didn't reach normal levels(P<0.05).Conclusion:1.Electro-acupuncture can quickly increaseβ-endorphin content in the plasma,and improve theμreceptor expression of hypothalamic arcuate nucleus,while promoting the synthesis and release in the hypothalamus to improve the behavior of depressive model rats.2.β-endorphin may play a role in rapid-onset mechanism of electro-acupuncture.