Effect of electroacupuncture intervention on ERK 1/2 signaling and TNF-α and IL-1β protein levels in the substantia Nigra in rats with Parkinson's Disease

Objective: To observe the effect of electroacupuncture(EA) on phosphalized extracellular regulated protein kinases(p-ERK) 1/2 signaling pathway and tumor necrosis factor (TNF)-α and IL-1β protein levels in the substantia nigra (SN) in rats with Parkinson's disease (PD), so as to explore its mechanism underlying improvement of PD.

Methods: 32 male SD rats were randomly and averagely divided into normal control group, sham-operation group, model group and EA group. PD model was established by intra-dermal-injection of rotenone(1 mg/kg, dissolved in DMSO and saline, concentration: 0. 25 mg/mL) at the nape, once daily for 14 days. EA (2 Hz, 2 mA) was applied to "Fengfu"(GV 16)and "Taichong"(LR 3) for 20 min, once daily for 14 days. For sham-operation group, subcutaneous injection of the same dose of DMSO and saline was given in the same way. The expression levels of tyrosine hydroxylase (TH), p-ERK 1/2, inflammatory cytokines TNF-α and IL-1P proteins of the SN tissue were detected using Western blot. The rat's horizontal and vertical movement ability was assessed using open-field tests.

Results: The horizontal and vertical movement scores were significantly lower in the model group than in the normal control group, and markedly higher in the EA group than in the model group (P<0. 05). Compared with the normal control group, the expression level of TH protein in the SN was significantly reduced in the model group( P<0. 05 ),while the expression levels of p-ERK 1/2, TNF-α and IL-1β proteins were significantly increased in the model group(P<0. 05). After EA intervention, the expression level of TH protein was significantly increased(P<0.05),and those of p-ERK 1/2, TNF-α and IL-1β proteins were significantly down-regulated(P<0. 05) in the EA group compared to the model group.

Conclusions: EA therapy may improve PD rats' movement ability, which may be associated with its effects in down-regulating the expression levels of p-ERK 1/2, TNF-α and IL-1β proteins and up-regulating the expression of TH protein in the SN.