Effect of dexmedetomidine pretreatment on inflammatory visceral pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effect of dexmedetomidine pretreatment on inflammatory visceral pain in rats. Methods Forty healthy male Wistar rats, weighing 200-300 g, aged 6-8 weeks, were divided into 5 groups ( n=8 each) using a random number table method: control group ( group C) , visceral pain group ( group VP ) , dexmedetomidine 1 μg∕kg group ( group Dex1 ) , dexmedetomidine 5μg∕kg group ( group Dex2) and dexmedetomidine 10μg∕kg group ( group Dex3) . The model of inflammato-ry visceral pain was established by intraperitoneally injecting 0. 9％ acetic acid 10 ml∕kg in VP, Dex1, Dex2 and Dex3 groups, and the equal volume of normal saline was given instead in group C. At 15 min be-fore intraperitoneal injection, dexmedetomidine 1, 5 and 10μg∕kg were injected via the tail vein in Dex1, Dex2 and Dex3 groups, respectively, and the equal volume of normal saline was given instead in C and VP groups. Behavioral changes of rats were observed within 60 min after the model was established, and viscer-al pain index ( VPI) was calculated. Blood samples were collected from the hearts at 180 min after establis-hing the model for determination of tumor necrosis factor-alpha ( TNF-α) concentrations in serum. The ani-mals were then sacrificed, and colons were obtained for examination of pathological changes with a light mi-croscope. Results Compared with group C, the VPI and serum TNF-α concentrations were significantly increased in VP and Dex1-2 groups, and the serum TNF-αconcentrations were significantly increased ( P<0. 05), and no significant change was found in VPI in group Dex3 (P>0. 05). Compared with group VP, the VPI and serum TNF-α concentrations were significantly decreased (P<0. 05), and the pathological changes of colon tissues were significantly attenuated in group Dex1-3. Compared with group Dex1, the VPI and serum TNF-α concentrations were significantly decreased ( P<0. 01) , and the pathological changes of colon tissues were significantly attenuated in Dex2-3 groups. Compared with group Dex2, the VPI and ser-um TNF-α concentrations were significantly decreased (P<0. 01), and the pathological changes of colon tissues were significantly attenuated in group Dex3. Conclusion Dexmedetomidine pretreatment can miti-gate inflammatory visceral pain in rats.