Autophagy regulation and anti-inflammatory effect of curcumin on the mouse with experimental autoimmune encephalomyelitis / 解放军医学杂志

ABSTRACT

Objective To investigate the anti-inflammatory effect of curcumin on the mouse with experimental autoimmune encephalomyelitis (EAE), and explore its mechanism of action. Methods Forty female C57BL/6 mice were randomly divided into EAE+DMSO group, EAE+curcumin group, DMSO group and curcumin group with10 mice in each group. Mice in EAE+DMSO group and EAE+curcumin group were used to establish the EAE model. DMSO group was the solvent control of EAE+DMSO group, and 0.2 ml 20% DMSO solution daily were intraperitoneally injected in the both groups a week after immunization; and mice in curcumin group and EAE+curcumin group were daily intraperitoneally injected with 10 mg/kg curcumin solution a week after immunization. From the date of immunization, the mice in each group were evaluated for clinical symptoms every day. Mice were anesthetized and sacrificed at the peak period of EAE (21 d), their spinal cord tissues were taken for HE staining, serum concentrations of INF-γ and IL-17 were measured by ELISA, spleen lymphocytes were sorted for CD4+ T. The expression levels of Atg-5 mRNA and LC3-Ⅱ mRNA in spinal cord tissue were determined by RT-PCR, and of LC3-Ⅱ was estimated by immunohistochemical staining. Results Based on the successful establishment of mouse EAE model, there were no obvious neurological injury symptoms in DMSO group and curcumin group, and no inflammatory reaction by HE staining in spinal cord tissue. The clinical symptom score in EAE+DMSO group (3.312±0.347) was significantly higher than that in DMSO group (P0.05). The serum concentrations of INF-γ and IL-17 were significantly higher in EAE+DMSO group (210.56±47.74 and 218.09±35.33) than in DMSO group (P0.05); Compared with the DMSO group, the Atg-5 level (0.70±0.06), LC3-Ⅱ gene expression level (0.67±0.10) and LC3-Ⅱimmunohistochemical positive cell count [(8.33±2.05)/HP] were down-regulated significantly in EAE+DMSO group (P<0.05); the Atg-5 level (1.56±0.08), LC3-Ⅱ gene expression level (1.99±0.11) and LC3-Ⅱimmunohistochemical positive cell count [(19.67±1.70)/HP] raised significantly in EAE+curcumin group when compared with that in EAE+DMSO group (P<0.05). Conclusions Curcumin may relieve the clinical nerve function injury in the course of EAE, downgrade the peripheral and central inflammatory response, meanwhile up-regulate the expression levels of Atg-5 and LC3-Ⅱ and upgrade the autophagy level of central nerve cells. Thus the inflammatory injury process in EAE course may be limited.