In our study, lupus mice treated with coptisine showed significant improvement of renal function and structure, which was reflected by reductions in the rate of urinary protein to creatinine, glomerular size, the extent of mesangial matrix expansion and glomerulosclerosis, the deposition of IgG and C3 and the expression of pro-inflammatory cytokines. The gene discussed is C3; the disease is systemic lupus erythematosus.