Master of Science (MS)
Biomedical and Veterinary Medical Sciences - Veterinary Clinical Sciences
Objective: Our in vitro study evaluated chondrocyte death in canine articular cartilage exposed to 0.5% bupivacaine without (B) and with methylparaben (BP) and compared the viability with intact (SI) and mechanically debrided surfaces (SR). We hypothesized that B or BP would cause chondrocyte death in vitro in a time dependent manner and that chondrocyte death would be increased in SI osteochondral cores compared to SR. Materials and Methods: Intact cartilage cores with underlying subchondral bone were collected aseptically from both humeral heads of 16 fresh canine cadavers. Joints from each dog were randomly assigned to SI or SR. Ten osteochondral cores were harvested from each humeral head. Synovium and one core were examined to verify joint health. The remaining 9 cores were exposed at random to canine chondrocyte culture media (CCCM), B, or BP for 5, 15, or 30 minutes. The pH of each solution was measured at the beginning and end of each treatment. The treated cartilage was stained with ethidium and calcein and digital images were captured under laser confocal microscopy. Three zones of each core (superficial, middle, deep) were examined. The number of dead/ (live+dead) chondrocytes were counted with digital image editing software. The proportion of dead cells (chondrocyte death) was expressed as a percentage and transformed to follow a normal distribution for analysis. Results: Superficial zone of SI—The BP had significantly higher %cell death at 5 minutes (47.7%) than B (23.6%) or CCCM (25.4%) but by 30 minutes B (53.8%) and BP (62.5%) was similar while CCCM (20.0%) remained unchanged and significantly lower. Superficial zone of SR—The BP had significantly higher %cell death at 30 minutes (59%) compared to 5 minutes (37.7%); The BP had significantly higher %cell death at 30 minutes (59%) than CCCM (28.9%). The pH was significantly lower for B (5.81-6.52) and BP (5.36-6.36) than CCCM (7.51-7.85). Summary and Clinical Relevance: This study shows a cytotoxic effect of 0.5% bupivacaine with and without preservative on canine articular chondrocytes in a time dependent manner in vitro. Intra-articular administration of 0.5% bupivacaine with or without preservative should be used with caution.
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Hennig, Geoffrey Stuart, "Chondrocyte death in canine osteochondral explants exposed to 0.5 percent bupivacaine" (2009). LSU Master's Theses. 377.