L-Monomethyl-arginine decreases apoptosis of chondrocytes by altering Bax and Bcl-2 expression in osteoarthritis of rabbit knee

Previous studies found that NG-monomethyl-L-arginine (L-NMMA) treatment inhibits progression of osteoarthritis. Here, we aimed to explore the effects of L-NMMA on chondrocyte apoptosis and Bax and Bcl-2 mRNA expression in rabbits with knee osteoarthritis. Knee osteoarthritis was induced in 24 healthy rabbits by Hulth method, and rabbits were randomly divided into control (n = 12) and experimental (n = 12) groups. Once weekly, knee joints of control rabbits were injected with saline solution, while knees of experimental rabbits were injected with L-NMMA. Knee joint samples were collected after 6 weeks of treatment. Apoptosis of chondrocytes was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and Bax and Bcl-2 mRNA expression by in situ hybridization. The results show that the mean rate of chondrocyte apoptosis in knees of the experimental rabbits was significantly lower than that of the control rabbits (P<0.05). Additionally, Bax expression decreased and Bcl-2 expression increased in the experimental group (P<0.05). In brief, LNMMA can inhibit apoptosis of joint chondrocytes through changes in the expression of apoptosisrelated genes. Thus, this molecule offers the potential for treating osteoarthritis. Key words: NG-Monomethyl-L-arginine, knee osteoarthritis, chondrocyte, apoptosis-related regulatory gene.