Effect of aloe-emodin on the proliferation and apoptosis of human synovial MH7A cells; a comparison with methotrexate

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial hyperplasia. Methotrexate (MTX), an antifolate derivative, is used for the treatment of RA, as it exerts antiproliferative efftects on lymphocytes and synovial cells. Aloe-emodin (AE) is a primary component of anthraquinones in Aloe vera and exerts antiproliferative and apoptotic effects on various tumor cells. In the present study, the effect of AE on the proliferation and apoptosis of MH7A human RA synovial cells was examined. In addition, the effect of AE was compared with that of the established RA therapeutic MTX. MH7A cells were incubated with 5, 10, 20 or 40 mu M AE, or 0.01, 0.05, 0.1 or 1 mu M MTX, for 24, 48 or 72 h. Subsequently, total cell numbers were assessed using trypan blue staining and Cell Counting kit-8. Furthermore, MH7A cells incubated with AE or MTX for 48 h were evaluated for apoptosis following Annexin V/propidium iodide (PI) staining, and for cell cycle distribution following PI staining. The results indicated that >= 10 mu M AE and >= 0.05 mu M MTX effectively decreased the numbers of viable MH7A cells. In addition, 40 mu M AE and 1 mu M MTX induced apoptosis in MH7A cells. Cell cycle analysis revealed that = 20 mu M AE induced G2/M phase arrest, whereas = 0.1 mu M MTX induced S phase arrest. These observations suggested that AE treatment inhibited the growth of MH7A cells by arresting the cell cycle at a different checkpoint compared with MTX treatment. Thus, AE may be a potential therapeutic agent for the treatment of RA, and may be complimentary to MTX, based on its antiproliferative effect on synovial cells.