Analgesic Effects Of Dexmedetomidine Combined With Sufentanil Intrathecally Injection On CCI Model In Rats

Objective: To study the analgesic effect of dexmedetomidine combined with sufentanilintrathecal injection on CCI model of rats.Methods: Intrathecal catheters were successfully inplanted in50male SD rats. All therats randomly were divided into five groups as follows: Sham group (Sham); modelcontrol group (CCI group); dexmedetomidine group (Dex group); sufentanil group(Suf group); combined treatment group (DS group). Rats in Dex group, Suf group andDS group were intrathecally injected respectively with dexmedetomidine2mg/(kg d), sufentanil1mg/d and dexmedetomidine1mg/(kg d)+sufentanil0.5mg/d daily at1～14d after CCI. The total capacity of each group of drugs was diluted into20ml,rats in CCI group were intrathecally injected with an equal volume of0.9%salinedaily. The paw mechanical withdrawal threshold (MWT) and thermal withdrawallatency (TWL) were measured30min after administration before operation and1,3,7, and14days after CCI．Five in each group were sacrificed at7and14days afteroperation and the expressions of Fos protein in the dorsal root ganglion (DRG) wereexamined with the immunohistochemical methods.Results: The MWT and TWL at each time points were significantly decreased andc-Fos protein expressions in DRG7days post-operation were significantly higherthan group CCI, Dex, Suf and DS compared with group Sham (P<0.05). MWT andTWL were significantly increased and c-Fos protein expressions in DRG weresignificantly lower in group Dex, Suf and DS compared with group CCI (P<0.05).MWT and TWL significantly increased and c-Fos protein expressions decreased ingroup DS compared with group Dex and Suf.Conclusion: Conclusion: Combined intrathecal application of dexmedetomidine withsufentanil could produce a significantly synergistic analgesic effects.