超声造影评价右美托咪定对兔肾缺血/再灌注损伤时微循环灌注的影响

目的：应用超声造影定量分析技术评价右美托咪定（DEX）对兔肾缺血/再灌注（I/R）损伤时微循环灌注的影响。方法新西兰家兔24只随机分成3组（每组8只）：对照组、肾缺血/再灌注损伤组（I/R组）和右美托咪定组（DEX组）。I/R组和DEX组切除右肾建立左肾缺血再灌注损伤模型。DEX组在肾缺血前30 min腹腔注射10μg/kg右美托咪定。再灌注24 h后，测定肾脏大小和肾血流阻力（RI），超声造影观察肾皮质灌注，时间-强度曲线定量分析达峰时间（TTP）、峰值强度（PSI）、曲线上升斜率（Grad）和曲线下面积（AUC）。取肾脏观察病理改变。结果与对照组比较，I/R组和DEX组肾大小和病理改变明显，RI增高， TTP延长，PSI和Grad降低，AUC显著增加（P<0.05）；与I/R组比较，DEX组肾大小和病理改变明显改善，RI降低，TTP缩短， PSI和Grad增高，AUC减少（P<0.05）。结论超声造影结合时间-强度曲线参数能动态定量分析右美托咪定改善兔肾缺血/再灌注损伤时的微循环灌注。

Effects of dexmedetomidine on microcirculatory perfusion in rabbits with renal ischemia/reperfusion injury:quantitative evaluation with contrast-enhanced ultrasound

Objective To investigate the effects of dexmedetomidine on renal microcirculatory perfusion in rabbits with renal ischemia/reperfusion (I/R) injury rabbit by quantitative analysis of contrast-enhanced ultrasound (CEUS). Methods Twenty-four New Zealand rabbits were randomly divided into 3 groups (8 in each), including a control group, renal I/R injury group and dexmedetomidine group. In the latter two groups, the right kidney of the rabbits was resected and I/R injury was induced in the left kidney. In dexmedetomidine group, the rabbits received an intraperitoneal dose of 10 μg/kg dexmedetomidine 30 min before renal ischemia, and 24 h after reperfusion, the renal size and renal artery resistance (RI) were measured, and renal cortex perfusion was observed by CEUS. The time-to-peak intensity (TTP), peak signal intensity (PSI), gradient between start frame to peak frame (Grad) and area under the curve (AUC) were quantitatively analyzed using the time-intensity curves. Pathological changes of the kidney were also observed. Results Compared with the control group, the rabbits in I/R and dexmedetomidine groups showed distinct changes of the renal size with obvious renal pathologies. RI, PPT and AUC all increased, and PSI and Grad decreased significantly in I/R and dexmedetomidine groups (P<0.05). Compared with I/R group, obvious improvement of the renal size and renal pathologies were observed in dexmedetomidine group, which showed significantly decreased RI, PPT and AUC and increased PSI and Grad (P<0.05). Conclusion CEUS combined with the time-intensity curve parameters allows quantitative and dynamic analysis of the protective effects of dexmedetomidine on microcirculatory perfusion in rabbits with renal I/R injury.