Effects Of Lidocaine And Verapamil On Secretion Of MMP-3 And TIMP-1 By Cultured Rabbit Articular Chondrocytes

Backgroud:Ion channels are transmembranous proteins located on the memberane of plant and animal cells.The pathways of inorganic ions across the membrane include active transport and passive transport. Passive transport pathway was mediated by ion channels.The ion channels are selective for certain types of ions.The task of the ion channels is to make diffusion of various anorganic ions,especially Na+,K+,Ca2+ and Cl" through the lipid double layer of the cell membrane.The chondrocytes belongs to non-excitable cell systems.A resting membrane potential is present on the cell membrane under physiological conditions.Ion channels,which is essential for the maintenance of membrane potential,have already been proven to exist in the membrane of human and animals' chondrocytes.Lidocaine,which is known to be a voltage dependent Na+ channel blocker,influence the resting membrane potential of chondrocyte.Moreover,lidocaine plays roles in chondrocyte proliferation,apoptosis and metabolism.Recently, intra-articular injection of lidocaine was proven to be effective for postoperative analgesia and widely used.But published clinical case reports have suggested potential adverse effects of intra-articaular infusion of lidocaine on articular cartilage.Therefore,effects of lidocaine on articular chondrocytes are more concerned.Verapamil, voltage-gated L-type calcium channel blocker,has been demonstrated that have a role in resting membrane potential maintenance,chondrocytes metabolism and, in major cell functions such as replication and apoptosis. More particularly,it is shown that Ca2+ and Ca2+ channels are involved in the relationship between stress or electrical stimuli and chondrocytes.Therefore,many studies try to investigate the etiology and therapeutics of osteoarthritis on the base of Ca2+ channel activity.Of notes, cartilage degradation is a process resulting from an imbalance of anabolic and catabolic changes in the articular cartilage matrix.The imbalance of MMP-3 and TIMP-1 has been proven important in this process.But the Effects of lidocaine and verapamil on secretion of MMP-3 and TIMP-1 by articular chondrocytes is still unclear.Objectives:To determine the effects of 1.Ommol/L lidocaine and 0.25mmol/L verapamil on synthesis of MMP-3 and TIMP-1 by cultured rabbit chondrocytes,investigate the influence of Na+,Ca2+ channel activity on integrity of articular cartilage,provide evidence for the clinical administration of lidocaine and verapamil.Methods:Chondrocytes were isolated from the knee joints of three two-month New Zealand Rabbit knees with sterile operation.Chondrocytes were cultivated in 24 well plates for 7 days, cell density of 5×104/ml. Divide into three groups :control group, 1.Ommol/L lidocaine group and 0.25mmol/L verapamil group. The medium concluding different agents was changed on the 7th culture day,incubated for 24h,48h or 72h under 1.Ommol/L lidocaine,0.25mmol/L verapamil,and whith neither as control.Then measure the MMP-3 and TIMP-1 contents of each supernatant samples by ELISA.Results:Compare with control group,1.Ommol/L lidocaine induced MMP-3 elevated in supernatant at 24h and 48h (p<0.05),had no effect on TIMP-1 content at all three time point; 0.25mmol/L verapamil induced MMP-3 and TIMP-1 in supernatant at 24h,48h and 72h(p<0.05),except MMP-3 at 48h.Conclusions:l.Ommol/L lidocaine elevated secretion of MMP-3 by cultured normal rabbit articular chondrocytes,and had no effect on secretion of TIMP-1;0.25mmol/L verapamil elevated secretion of MMP-3 and TIMP-1 by articular chondrocytes; Na+,Ca2+ channel activity had effects on secretion of MMP-3 and TIMP-1 by articular chondrocytes, voltage dependent Na+ channel blocking may induce degradation of extracellular matrix of articular cartilage.