An evaluation of the delayed effect of intra-articular injections of lidocaine (2%) on articular cartilage: an experimental study in rabbits.

Lidocaine is commonly injected into the joints as an analgesic. The aim of the present study was to evaluate the delayed effect of intra-articular injections of lidocaine (2%) on articular cartilage in rabbit knees. Ten rabbits were divided into two groups, each group containing five animals. Two milliliters of normal saline solution was injected into both knee joints of animals in group one (control group), and 2 ml of lidocaine was injected into both knee joints of animals in group two (case group). After 8 weeks, the articular cartilage of the distal femur was harvested and analyzed through confocal microscopy and real-time polymerase chain reaction to evaluate the viability and function of chondrocytes, respectively. Confocal microscopy showed a significant decrease in the number of live cells caused by lidocaine (P ≤ 0.001). The changes in gene expression of collagen types II (COL II) and aggrecan were significant in group two (P = 0.008 and P = 0.002, respectively). According to the results, the delayed in vivo effect of lidocaine on chondrocyte is to reduce live chondrocytes and change in the gene expression of COL II and aggrecan.