Abstract: Objective To probe into the protective effect of dexmedetomidine on ischemia-reperfusion injury of posterior intercostal artery perforator flap in rats. Methods Twenty-four SD rats were randomly divided into control group, Ischemia-reperfusion group (I/R group) and dexmedetomidine+Ischemia-reperfusion intervention group (DEX+I/R group). Rats in control group was prepared with the posterior intercostal artery perforator flap; rats in I/R group were prepared with vascular pedicle clipping for 6 hours after flap harvesting, and the DEX+I/R group was treated with dexmedetomidine 100 μg/kg after ischemia process and repeated dosing 24 hours later. On day 7 after flap construction, survival rate of the flap was determined by gross observation; HE staining was used to observe the pathological condition of rat skin flap tissue; TUNEL fluorescence staining was used to detect the apoptosis of rat skin flap tissue; contents of SOD and MDA in rat plasma were determined by enzyme-linked immunosorbent assay. The expressions of apoptosis-related proteins (C-caspase-3, Bcl-2) and PI3K/Akt pathway proteins (PI3K, pAkt/Akt) in rat skin flap tissues were detected by western blotting. Results Survival rate of the flap in control group, I/R group and DEX+I/R group was (94.15±2.28)%, (38.15±10.48)% and (57.71±10.22)%. Compared with control group, the flap survival rate in I/R group was significantly lower (P＜0.001); compared with I/R group, the flap survival rate in DEX+I/R group was significantly higher (P=0.006). At the distance of 1cm from vascular pedicle, the apoptosis rate of skin flap tissue in I/R group was higher than that in control group (P＜ 0.001); the apoptosis rate of skin flap tissue in DEX+I/R group was lower than that in I/R group (P＜ 0.001). At the distance of 2 cm from vascular pedicle, the apoptosis rate of skin flap tissue in I/R group was higher than that in control group (P＜0.001); the apoptosis rate of flap tissue in DEX+I/R group was lower than that in I/R group (P=0.004). Compared with control group, SOD activity in serum of rats in I/R group was lower (P＜0.001); compared with I/R group, SOD activity in serum of DEX+I/R group was increased (P＜0.001). The serum MDA content in I/R group was higher than that in control group (P＜ 0.001); compared with I/R group, MDA content in serum of DEX+I/R group was decreased (P＜0.001). The expression of Bcl-2 (P=0.001), PI3K (P=0.003), Akt (P=0.023) and pAkt (P=0.002) in I/R group were lower compared with control group, while the expression of C-caspase-3 was significantly increased (P=0.002). The expression of Bcl-2(P=0.003), PI3K(P＜0.001), Akt(P＜0.001) and pAkt(P＜0.001) in I/R group were increased compared with control group, while the expression of C-caspase-3 was significantly decreased (P＜0.001). Conclusion Dexmedetomidine can alleviate ischemia-reperfusion injury of posterior intercostal artery perforator flap in rats.

Key words: posterior intercostal artery perforator flap, ischemia-reperfusion injury, dexmedetomidine