Effects of dexmedetomidine on bupivacaine-induced myotoxicity and inflammation in rats

Aims: The increasing use of regional anesthesia techniques has heightened concern regarding local anesthesia-related tissue damage. Bupivacaine is widely used because of its long duration of action and high potency, however it is associated with a high myotoxic potential. This study aims to evaluate whether the addition of dexmedetomidine as an adjuvant to bupivacaine during peripheral block may influence bupivacaine-induced myotoxicity and inflammation. Methods: Twenty-eight Wistar albino rats were allocated into four equal groups. Group C received 0,2 mL of 0,9% normal saline, Group B received 0,2 mL of 0,25% bupivacaine, Group D received 0,2 mL of dexmedetomidine at a concentration of 0,005%, and Group BD received a combination of 0,25% bupivacaine and 0,005% dexmedetomidine. All injections were administered intramuscularly into the right gastrocnemius muscle. After 48 hours, muscle tissues were harvested for histopathological evaluation using the Modified Benoit Score. Serum creatine phosphokinase (CPK) and C-reactive protein (CRP) levels were measured. Results: Group B demonstrated the highest histopathological damage scores. Scores in Group BD were lower than those in Group B but higher than those in Groups C and D. Serum CPK levels were significantly higher in Group B compared with the other groups. No statistically significant differences were observed among the groups with respect to CRP levels. Conclusion: Dexmedetomidine was associated with a reduction in bupivacaine-induced myotoxicity in rats, as supported by histopathological and biochemical findings. These results suggest that dexmedetomidine may have the potential to reduce muscle injury when used as an adjuvant to local anesthetics, although further experimental and clinical studies are required.