Effects Of Estrogen And G Protein Coupled Receptor 30 On Chronic Migraine In Rats

Objective: Previous studies have found that estrogen and G-protein-coupled receptor 30 play an important role in a variety of pain models.In this experiment,the effects of estrogen and GPR30 on headache indexes of chronic migraine model in rats were studied,and the effects of estrogen and GPR30 on chronic migraine and its possible mechanism were explored.Methods:All rats were ovariectomized,and the rats with sexual cycle were removed by vaginal smear every day within 7 days after operation.The remaining rats were randomly divided into 5 groups with 8 rats in each group.The drug was administered continuously for 14 days after operation.Vehicle: intraperitoneal injection of PBS 20 mg / day,contains DMSO(less than 0.1%).IS: daily epidural injection of inflammatory soup 2 μ L,intraperitoneal injection of PBS 20 mg / kg.E2: daily epidural injection of inflammatory soup 2 μ L,intraperitoneal injection of E2 1mg / kg.G1: daily epidural injection of inflammatory soup 2 μ L,intraperitoneal injection of G1 20 mg / kg.G15: daily epidural injection of inflammatory soup 2 μ L,intraperitoneal injection of E2 1mg/kg,G15 5mg/kg.Von Frey filament was used to detect the pain threshold of periorbital and hindpaw skin every day within 14 days,and the behavioral score of rats was observed.After the last administration,the serum of rats was taken to detect the contents of estradiol,IL-10 and TNF-α.After the last administration,immunohistochemistry,Western blot and RT-PCR were used to detect the protein expression and m RNA level of GPR30,CGRP and c-fos in trigeminal ganglion and thalamus.Results:1.Compared with Vehicle group,the pain threshold of periorbital and hindfoot decreased in IS group,the periorbital pain threshold decreased significantly from the third day,and the hindpaw pain threshold decreased significantly from the fourth day.After 14 days of administration,the pain threshold of periorbital and hindpaw tended to be stable.Compared with Vehicle group,the score of autonomic behavior response in IS group was significantly higher than that in IS group(P<0.05).Compared with IS group,the threshold of periorbital pain and hindfoot pain was higher and the behavioral score was lower in E2 and G1 groups.The results suggest that repeated hard brain stimulation can successfully simulate the attack of chronic migraine,indicating that the model is successful.2.Seven days after ovariectomy,there was no significant difference in serum estrogen level among the three groups.After the last administration,compared with Vehicle group,the level of estrogen in IS group had no significant change.The level of serum estrogen in E2 group and G15 group was significantly higher than that in IS group(P < 0.05).The results suggest that estrogen can significantly increase the level of estrogen in rats.3.Blood samples were taken after the last administration.Compared with Vehicle group,IL-10 decreased,TNF-α increased and TNF-α / IL-10 increased in IS group(P < 0.05).Compared with IS group,the content of IL-10 in E2 group and G1 group increased,the content of TNF-α in E2 group and G1 group decreased,and the ratio of TNF-α / IL-10 in E2 group and G1 group decreased(P < 0.05).Compared with E2 group,the content of TNF-α in G15 group increased(P < 0.05),but the content of IL-10 did not decrease significantly.4.After the last administration,compared with Vehicle group,the expression of CGRP and c-fos in TG and thalamus increased in IS group(P < 0.05),but there was no significant difference in GPR30 expression.Compared with IS group,the expression of GPR30 in TG and thalamus increased in E2 group and G1 group,while the expression of CGRP and c-fos decreased in E2 group and G1 group(P < 0.05).Compared with E2 group,the expression of GPR30 in TG and thalamus in G15 group decreased,the expression of CGRP increased and the expression of c-fos increased(P < 0.05).Conclusion:1.Exogenous administration of estrogen and activation of GPR30 can regulate the threshold of periorbital and hindpaw pain and regulate the expression of c-fos and CGRP in TG and thalamus.Estrogen and GPR30 have analgesic effect on chronic migraine in rats.2.Exogenous administration of estrogen and activation of GPR30 affect the levels of IL-10 and TNF-α.The balance of inflammatory factors may be an important mechanism by which estrogen and GPR30 receptors participate in chronic migraine.3.A certain dose of estrogen and G1 increased the expression of GPR30 in TG and thalamus,and had analgesic effect on model rats.G15 inhibited the expression of GPR30 and affected the blocking effect of estrogen on headache in model rats.Estrogen plays a regulatory role in chronic migraine through GPR30.