[Effect of equipotent doses of bupivacaine and ropivacaine in high-fat diet fed neonatal rodent model]. / Efeito de doses equipotentes de bupivacaína e ropivacaína em modelo de roedor neonatal alimentado com dieta rica em gordura.

OBJECTIVES: The increase in the prevalence of obesity presents a significant health and economic problem. Obesity has been reported to be a major contributor to variety of chronic diseases. Childhood obesity has been rising over the past decades leading to various complications in health. Millions of infants and children undergo surgery every year on various health grounds. The present investigation was undertaken to evaluate the effect of spinal anesthesia of equipotent doses of ropivacaine and bupivacaine on over-weight neonatal rats. METHODS: The Sprague-Dawley rat pups were overfed on high fat diet to induce obesity. Behavioral assessments for sensory and motor blockade was made by evaluating thermal and mechanical withdrawal latencies at various time intervals following intrathecal injections of bupivacaine (5.0mg·kg-1) and ropivacaine (7.5mg·kg-1) in P14 rats. Spinal tissue was analyzed for apoptosis by determination of activated caspase-3 using monoclonal anti-activated caspase-3 and Fluoro-Jade C staining. Long-term spinal function in P30 rat pups was evaluated. RESULTS: Exposure to intrathecal anesthesia in P14 increased thermal and mechanical latencies and was observed to increase apoptosis as presented by increase in activated caspase-3 and Fluro-Jade C positive cells. Significant alterations in spinal function were observed in high fat diet-fed pups as against non-obese control pups that were on standard diet. Bupivacaine produced more pronounced apoptotic effects on P14 pups; ropivacaine however produced long lasting effects as evidenced in motor function tests at P30. CONCLUSION: Ropivacaine and bupivacaine induced spinal toxicity that was more pronounced in over-fed rat pups as against normal controls.