This in vivo study showing reduced chondrocyte density without cartilage tissue loss six months after a single intra-articular injection of 0.5% bupivacaine suggests bupivacaine toxicity. The effects of bupivacaine were milder than those of an injection of 0.6% monoiodoacetate, which resulted in chondrolysis over the same time period.

Abstract-Osteopontin (OPN) is a cytokine upregulated in diabetic vascular disease. To better understand its role in vascular remodeling, we assessed how OPN controls metalloproteinase (MMP) activation in aortic adventitial myofibroblasts (AMFs) and A7r5 vascular smooth muscle cells (VSMCs). By zymography, OPN and tumor necrosis factor (TNF)-␣ preferentially upregulate pro-matrix metalloproteinase 9 (pro-MMP9) activity. TNF-␣ upregulated pro-MMP9 in AMFs isolated from wild-type (OPN ϩ/ϩ ) mice, but pro-MMP9 induction was abrogated in AMFs from OPN Ϫ/Ϫ mice. OPN treatment of VSMCs enhanced pro-MMP9 activity, and TNF-␣ induction of pro-MMP9 was inhibited by anti-OPN antibody and apocynin. Superoxide and the oxylipid product 8-isoprostaglandin F 2 ␣-isoprostane

Intra-articular injections of corticosteroids and local anesthetics are widely used in clinical practice. This in vitro study provides information on the potential effects of these drugs on articular cartilage.

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