三氟淫羊藿素通过α7nAChR抑制完全弗氏佐剂诱导脊髓小胶质细胞的激活作用

Effect of Trifluoro-icaritin inhibits complete Freund's adjuvant-induced microglial activation by activating α7nAChR in the spinal cord of rats

目的:探讨三氟淫羊藿素(Trifluoro-icaritin,ICTF)是否通过脊髓α7nAChR抑制完全弗氏佐剂(complete Freund's adjuvant,CFA)诱导小胶质细胞的激活作用。方法:首先将雄性SD大鼠随机分为3组:Ctrl组、CFA组和CFA+ICTF组。给予CFA+ICTF组的大鼠连续腹腔注射ICTF(3 mg·kg^(-1))21 d,并于第21 d取各组大鼠脊髓(L4~L6),应用qRT-PCR和Western blot检测CD11b的mRNA和蛋白表达水平。然后将雄性SD大鼠随机分为2组:CFA+ICTF+PBS组和CFA+ICTF+α-Bgtx组。将大鼠提前5 d进行鞘内置管,CFA造模后6 h连续腹腔注射ICTF(3 mg·kg^(-1))21 d并在第14天开始分别鞘内注射PBS和α7nAChR的抑制剂α-Bgtx,每天1次连续注射7 d。于第21 d取各组大鼠脊髓(L4~L6),应用Western blot检测CD11b的蛋白表达。结果:与Ctrl组相比,CFA组大鼠脊髓CD11b的mRNA和蛋白表达水平上调(P<0.01),而与CFA组相比,CFA+ICTF组大鼠脊髓CD11b的蛋白表达水平下调(P<0.001)。结论:α7nAChR的抑制剂α-Bgtx反转了ICTF下调CD11b表达的作用,提示ICTF可能通过α7nAChR抑制小胶质细胞的激活来缓解慢性炎性痛。

Objective:To investigate whether the inhibitory effect of Trifluoro-icariin(ICTF)on complete Freund’s adjuvant(CFA)-induced chronic inflammatory pain via activating spinal α7 nicotinic acetylcholine receptor(α7nAChR)could suppress microglial activation.Methods :Firstly,male SD rats were randomly divided into Control Group,CFA Group,and CFA+ICTF Group. The rats in CFA+ICTF Group were intraperitoneally injected with ICTF(3 mg·kg-1)once daily for 21 consecutive days. On the 21 st day,the spinal cord(L4~L6)of rats in each group was taken,and the mRNA and protein expression levels of CD11 b were detected by qRT-PCR and Western blot. Secondly,male SD rats were randomly divided into CFA+ICTF+PBS Group and CFA+ICTF+α-Bgtx group. The rats in the two groups were intraperitoneally given with ICTF(3 mg·kg-1)once daily for 21 consecutive days,and then intrathecal injection(i. t.)of α7nAChR antagonist alpha-bungarotoxin(α-Bgtx,1. 0 mg·kg-1)from the 14 th day to rats once daily for 7 consecutive days. On the 21 st day,the spinal cord(L4~L6)of rats in each group was taken,and the protein expression level of CD11 b was detected by Western blot.Results :Compared with the Ctrl group,the expression of CD11 b mRNA and protein in the spinal cord of rats from the CFA Group were significantly enhanced(P<0. 01),while the expression of CD11 b protein in the spinal cord of rats from the CFA+ICTF Group was obviously decreased(P<0. 001).Conclusion:α-Bgtx,an inhibitor of α7nAChR,reverses the downregulation of CD11 b protein induced by ICTF,suggesting that ICTF might inhibit the activation of microglia by α7nAChR in the spinal cord.