人参皂苷Rd的中枢镇痛作用及其与GABA_(B)受体相关机制研究

A study on central analgesia effect of ginsenoside Rd and its GABA_(B) reportor-related mechanism

目的探讨人参皂苷Rd(GSRd)的中枢镇痛作用及其与γ氨基丁酸B受体(GABA_(B)R)相关作用机制。方法50只小鼠随机均分为五组,侧脑室分别注射GSRd10mg/kg(GSRd低剂量组)、20mg/kg(GSRd中剂量组)、40mg/kg(GSRd高剂量组)、吗啡2mg/kg(吗啡组)和等量生理盐水(NS组),记录五组小鼠缩尾反应潜伏期(TCL),采用ELISA法检测除吗啡组外四组小鼠GSRd对脑组织GABA含量的影响。另取40只小鼠随机均分为四组:GSRd高剂量组、GSRd高剂量+GABA_(B)R激动剂巴氯芬(BAC)组(GSRd给药15min后每只小鼠注射BAC0.2μg)、GSRd高剂量+拮抗剂法克罗芬(PHAC)组(GSRd给药15min后每只小鼠注射PHAC0.5μg)和NS组,记录四组小鼠TCL。再取20只小鼠随机均分为GSRd高剂量组和NS组,采用免疫组化染色检测GSRd对丘脑GABA_(B)R_(2)阳性细胞的影响,采用Westernblot法检测GSRd对GABA_(B)R_(2)蛋白表达的影响。结果与NS组比较,GSRd高剂量组给药后可延长小鼠的TCL(P<0.05),GSRd中剂量组给药30min和60min可延长小鼠的TCL(P<0.05),GSRd低剂量组小鼠TCL无统计学差异(P>0.05)。与NS组比较,GSRd高剂量组和GSRd高剂量+BAC组小鼠TCL延长(P<0.05),给药后30min时TCL延长最明显,且持续时间均可达到120min。与给药前比较,GSRd高剂量组和GSRd高剂量+BAC组给药后可延长小鼠TCL(P<0.05),而GSRd高剂量+PHAC组给药后小鼠TCL无统计学差异(P>0.05)。ELISA法检测结果显示,与NS组比较,GSRd高剂量组和GSRd中剂量组小鼠脑组织GABA含量升高(P<0.05),而GSRd低剂量组无统计学差异(P>0.05)。免疫组化染色和Western blot检测结果显示,与NS组比较,GSRd高剂量组小鼠丘脑GABA_(B)R_(2)阳性细胞比例和脑组织中GABA_(B)R_(2)蛋白表达增高(P<0.05)。结论GSRd具有中枢镇痛作用,GABA_(B)R参与了GSRd的镇痛作用。

Objective To investilate the central analgesic effect of ginsenoside Rd(GSRd)and its gamma aminobutyric acid B receptor(GABA_(B)R)related mechanism.Methods Fifty mice were randomly divided into five groups.The mice were intracerebroventricularly injected with different doses of GSRd 40 mg/kg(group A),20 mg/kg(group B)and 10 mg/kg(group C),and morphin 2 mg/kg(group M),and normal saline(group NS).The tail contraction latency(TCL)of five groups of mice was recorded,and the effect of GSRd on GABA content in brain tissues of four groups of A,B,C,NS was detected by ELISA.Another 40 mice were randomly divided into four groups of D(GSRd 40 mg/kg),E(GSRd 40 mg/kg+BAC 0.2μg each mouse after 15 minutes of GSRd administration),F(GSRd 40 mg/kg+PHAC 0.5μg each mouse after 15 minutes of GSRd administration)and NS.The TCL of four groups of mice was recorded.Another 20 mice were randomly divided into group G(GSRd 40 mg/kg)and group NS.The effect of GSRd on GABA_(B)R_(2) positive cells in the thalamus was detected by immunohistochemical staining,and the effect of GSRd on GABA_(B)R_(2) protein expression was detected by Western blot method.ResultsCompared with group NS,the TCL of mice after administration was prolonged in group A(P<0.05),the TCL of mice after administration for 30 and 60 minutes was prolonged in group B(P<0.05),while group C had no significant effect on TCL(P<0.05).Compared with group NS,the TCL of mice in groups of D and E was prolonged(P<0.05),and the most obvious TCL was prolonged at 30 min after administration,and the duration reached 120 min in both groups.Compared with before administration,the TCL of mice in groups of D and E was prolonged after administration(P<0.05),while there was no significant change in TCL of mice in group F after administration(P<0.05).The ELISA test results showed that compared with group NS,the GABA content in the brain tissue of mice in groups of A and B was increased(P<0.05),while which had no statistically significant difference between group C and group NS(P<0.05).The immunohistochemistry staining and Western blot detection showed that the proportion of positive cells of GABA_(B)R_(2) in the thalamus and the protein expression of GABA_(B)R_(2) in the brain tissue of mice in group G were higher than those in group NS(P<0.05).Conclusion GSRd has central analgesic effect and GABA_(B)R participates in the analgesic effects of GSRd.