Effect of electroacupuncture on c-Jun amino terminal kinase signaling pathway and inflammatory cytokines interferon-γ in substantia nigra cells of rotenone-induced rats model of Parkinson's disease

Abstract

Objective To observe the effects of electroacupuncture (EA) on c-Jun amino terminal kinase (JNK) signaling pathway and inflammatory cytokines interferon-γ (IFN-γ) in substantia nigra (SN) cells of rotenone-induced rats model of Parkinson's disease (PD),and explore the underlying mechanism of EA on PD.Methods A total of 32 male Sprague-Dawley mice were randomly and evenly divided into a normal group,a shamoperation group,a model group and an EA group.Model group and EA group were injected intradermally with rotenone (1 mg/kg,dissolved in DMSO and saline,concentration:O.25 mg/ml) on the nape of neck.Sham-operation group was injected the same dose of DMSO and saline.Normal group had no intervention.EA group was applied to Fengfu (DU16) and Taichong (LR3) acupoints after the establishment of PD model in rats.Behavioral assessment was conducted after the treatments,the rats were sacrificed for sampling substantia nigra tissue to detect the expressions of tyrosine hydroxylase (TH),p-c-Jun amino terminal kinase (p-c-Jun) and interferon-γ(IFN-γ) protein with Western blotting (WB).Results Model rats showed significant PD syndrome characteristics,comparing with normal group and sham group,the difference was not statistically significant (P ＞ 0.05).The results of open box test showed that the scores of model group rats decreased significantly in terms of the horizontal movement [(19.12 ±2.34) points] and vertical locomotor activity [(5.27 ± 1.04) points] when compared with normal group and sham group,the difference was statistically significant (P ＜ 0.05).After EA treatment,locomotor activity of rats increased significantly when compared with model group (P ＜ 0.05),however,the normal group and sham group was not statistically and significantly different in locomotor activity (P ＞ 0.05).Compared with normal group,the expression of TH protein in (0.183 ± 0.0213) reduced significantly and the expressions of p-c-Jun (0.388 ± 0.0283) and IFN-γ protein(0.453 ± 0.0332) increased significantly in model group,the difference was statistically significant (P ＜0.05).Compared with normal group,the expression of TH protein(0.324 ± 0.0538) reduced and the expressions of p-c-Jun(0.207 ± 0.0592) and IFN-γ protein (0.239 ± 0.0215) increased in EA group,the difference was not statistically significant (P ＞ 0.05).Compared with model group,the expression of TH protein increased significantly in EA group(P ＜ 0.05),the expressions of p-c-Jun and IFN-γ protein reduced significantly in EA group(P ＜ 0.05).Conclusion EA therapy may reduce the expression of IFN-γ protein in SN of PD rats model by regulating the expression of JNK/mitogen-activated protein kinase (MAPK) pathway,which may delay the process of PD. Key words: Parkinson's disease; Electroacupuncture; Mitogen-activated protein kinase/c-Jun amino terminal kinase; Tyrosine hydroxylase; Interferon-γ