C3.MRL-Fas/J mice spontaneously develop high titers of anti-dsDNA, mild glomerular nephritis, and severe lymphoproliferation symptoms. This study aimed to compare the effects of long-term serial administration of human adipose tissue-derived mesenchymal stem cells (ASCs), and cyclophosphamide treatment in C3.MRL-Fas/J mice using a murine SLE model. C3.MRL-Fas/J mice were divided into saline (C), cyclophosphamide (Y), and ASC (H) treatment groups. Background-matched control C3H mice treated with saline (N) were also compared. The Y group showed the greatest improvement in disease parameters, but with damaged trabecular integrity. ASC transplantation reduced anti-dsDNA levels, glomerular C3 deposition and CD138 proportion significantly, without trabecular damage. Furthermore, both cyclophosphamide and ASC treatment significantly decreased the ratio of Th1/Th2 compared with the saline-treatment. The expression levels of miR-31-5p, miR-96-5p, miR-182-5p, miR-183-5p, and miR-379-5p were significantly higher, while those of miR150-5p were significantly lower in the C group than in the N group. The expression levels of miR-96-5p, miR-182-5p in the Y and H groups were significantly lower than in the C group. Thus, treatment with cyclophosphamide or ASC can change miRNAs and decrease miR-96-5p and miR-182-5p expression, as well as decreasing the CD138 proportion and the Th1/Th2 ratio, which might be involved in the therapeutic mechanism.