Objective: To observe the effect of transcutaneous otopoint electrostimulaiton (TCOES) on seizure frequency, immunoreactivity of hippocampal gliocytes and expression of proinflammatory cytokine interleukin-6(IL-6) and anti-inflammatory cytokine IL-10 in chronic temporal lobe epilepsy (CTLE) rats, so as to investigate its antiepileptic mechanism.
Methods: Thirty-six SD rats were randomly divided into control, model and TCOES groups (n=12 in each group). The CTLE model was established by intraperitoneal injection (i.p.i.) of lithium chloride (127.2 mg/kg), scopolamine (1 mg/kg, 20 h after the 1st injection) and pilocarpine (10 mg/kg, 30 min after scopolamine injection). Rats of the control group were treated by i.p.i. of normal saline. TCOES (1 mA, 20 Hz) was applied to bilateral otopoint "Heart"-"Lung"-"Subcortex" region for 20 min, once daily for 6 weeks. The epileptic attack was observed by a video monitoring system. The numbers of ionized calcium-binding adapter molecule-1 (Iba 1)-labeled microgliacytes and glial fibrillary acidic protein (GFAP)-labeled astrocytes in the CA 1 and CA 3 regions of hippocampus were counted under light microscope after immunostaining, and the expression levels of hippocampal IL-6 and IL-10 proteins and genes were determined by immunofluorescence and quantitative real-time PCR, respectively.
Results: After TCOES intervention, the seizure frequency was significantly decreased in comparison with pre-treatment(P<0.05), modeling-induced dramatic increase of the numbers of microgliacytes and astrocytes,IL-6 immunoactivity in the hippocampal CA 1 and CA 3 regions, and IL-6 mRNA expression in the hippocampus were significantly suppressed (P<0.05), and hippo-campal IL-10 immunoactivity and mRNA expression were considerably up-regulated in comparison with the model group (P<0.05).
Conclusions: TCOES intervention has an antiepileptic effect in CTLE rats, which may be associated with its effects in suppressing gliocyte proliferation, suppressing the expression of proinflammatory cytokine IL-6, and up-regulaiting the expression of anti-inflammatory cytokine IL-10 in the hippocampus.