The Intervention Effect Of Proteasome Inhibitor MG132 In Rats With Collagen-Induced Arthritis

Objective:To observe serum 20 S proteasome levels in patients with rheumatoid arthritis(RA),and to explore the intervention effect of proteasome inhibitor MG132 in rats with collagen-induced arthritis(CIA),which resembles human rheumatoid arthritis(RA).Methods:The serum 20 S proteasome levels were detected in 53 RA patients and 35 healthy persons by sandwich enzyme-linked immunosorbent assay(ELISA).2.Sixty-four female SD rats were randomly divided into four groups,including blank control group,CIA model group,MG132-treated group and MG132 control group,There were sixteen rats in each group.Rats in CIA model group and MG132-treated group were injected with type II collagen to established CIA rats.21 days after the initial immunization,the rats in the MG132-treated group were injected subcutaneously with 1 mg/kg MG132 once daily for 2 weeks.Rats in the MG132 control group were injected subcutaneously with MG132 in the same manner.42 days after the initial immunization,the change of paw-swelling and the arthritis scores were determined.liver and kidney functions were also monitored.The synovial pathology examination was performed with HE staining.The levels of serum TNF-α,IL-6 and IL-10 were measured by enzyme linked immunosorbent assay.The 20 S proteasome activity in synovial tissue was measured by fluorescence substrate assay.The expression of NF-κB/p65,IκBα in synovial tissue were analyzed by western blotting.Results:1.The serum 20 S proteasome levels were higher in RA patients than in healthy people(p<0.05). 2.Proteasome inhibitor MG132 significantly attenuated the severity of arthritis and histopathological changes in CIA rats. 3.Compared with the blank control group,the 20 S proteasome activity was increased significantly in the CIA model group(p<0.05), and decreased after injection of MG132. 4.The levels of TNF-α and IL-6 in the CIA model group were higher than the blank controlgroup(p<0.05),but the level of IL-10 was lower than the blank control group(p<0.05).After injected proteasome inhibitor MG132,the levels of TNF-α and IL-6 were decreased significantly,the level of IL-10 was increased significantly(p<0.01). 5.Compared with CIA rats,the expression of NF-κB/p65 significantly decreased in rats treated with MG132(p<0.01).6.Compared with the blank control group,the expression of IκBα protein decreased in CIA model group.After injected with MG132,the protein was significantly increased(p<0.01).7.Liver and kidney toxicities were not observed in normal rats injected with 1 mg/kg proteasome inhibitor MG132.Conclusions:1.RA patients showed high levels of 20 S proteasome.2.The proteasome inhibitor MG132 may attenuates the severity of arthritis and histopathological changes in CIA rats.These effects may be mediated through the inhibition of NF-κB activity.3.Injected subcutaneously with 1 mg/kg MG132 has no adverse effects in liver and kidney function in normal rats.