Department of Ultrasound, Huai'an First People's Hospital, Nanjing Medical University, Huaian 223300, Jiangsu, China.
Asian Pac J Trop Med. 2016 Feb;9(2):188-92. doi: 10.1016/j.apjtm.2016.01.006. Epub 2016 Jan 13.
To evaluate the renal ischemia reperfusion injury (IRI) in rabbits using the ultrasonic contrast technique and discuss the clinical value of ultrasonic contrast technique in the diagnosis of renal IRI by comparing the time-intensity curve of renal cortex and the expression of vascular endothelial growth factor (VEGF) of renal tissue.
Twenty 3-month-old New Zealand rabbits were randomly divided into 4 groups, namely Ctrl group, IRI-12 h, IRI-24 h and IRI-48 h groups. The two dimensional gray-scale ultrasonography was employed to determine and mark the position of rabbit kidney. Rabbits were given the intraperitoneal anesthesia with 20% urethane with the dosage of 5 mL/kg. The aseptic operation was performed after the local skin disinfection in the area of both kidneys. The right kidney of animals in the control group was excised without any treatment for the left kidney. After excising the right kidney of animals in groups of IRI-12 h, IRI-24 h and IRI-48 h, the aneurysm clip was used to clip the renal pedicle vessel of left kidney, in order to simulate the ischemia. Because of the tissue ischemia, it could be seen that the color of kidney was changed from bright red to dark red, which indicated the successful modeling of ischemia. The aneurysm clip was released after one hour of maintaining the ischemia. Then the kidney turned out to be bright red from dark red, which indicated that the reperfusion was completed. Taking this moment as the time of ischemia reperfusion, the wound was stitched up. A total of 12, 24 and 36 h after the operation, the two-dimensional and color Doppler flow imaging and ultrasonic contrast were employed for the examination. The dynamic changes of ultrasonic contrast were recorded. The quantitative analysis software (QontraXt) was adopted to analyze the time-intensity curve of echo at different positions of renal cortex. After the ultrasonic contrast testing, rabbits were put to death. The renal cortex tissue was isolated and the tissue RNA and total protein were extracted respectively. Real-time PCR and western blotting were used to detect the VEGF and the Pearson product moment correlation coefficient was used to measure the linear relationship between these two variables.
The ultrasonic contrast could clearly reflect the process of IRI. The results of testing at mRNA and protein level indicated that the expression of VEGF in IRI groups was significantly increased (P < 0.05) and the expression of VEGF was also increased by the time of reperfusion.
There is the certain correlation between the expression of VEGF and process of IRI. The correlation coefficient between the ultrasonic contrast parameters of AT and TTP and the relative expression of VEGF is over 0.9, which indicates the relatively high correlation. But there is no significant difference in the change of perfusion peak intensity between groups, which has no correlation with the expression of VEGF.
使用超声对比技术评估兔肾缺血再灌注损伤（IRI），并通过比较肾皮质的时间-强度曲线和肾组织血管内皮生长因子（VEGF）的表达，探讨超声对比技术在诊断肾 IRI 中的临床价值。
将 20 只 3 月龄新西兰兔随机分为 4 组，即对照组、IRI-12 h 组、IRI-24 h 组和 IRI-48 h 组。采用二维灰阶超声确定并标记兔肾位置。兔给予 20% 氨基甲酸乙酯腹腔内麻醉，剂量为 5 mL/kg。对双侧肾脏区域进行局部皮肤消毒后进行无菌操作。对照组动物的右肾切除，左肾不做任何处理。IRI-12 h、IRI-24 h 和 IRI-48 h 组动物的右肾切除后，用动脉瘤夹夹闭左肾蒂血管，模拟缺血。由于组织缺血，可见肾脏颜色由鲜红色变为暗红色，提示缺血模型成功建立。缺血 1 小时后松开动脉瘤夹，肾脏由暗红色变为鲜红色，提示再灌注完成。将这一刻作为缺血再灌注的时间，进行二维和彩色多普勒血流成像及超声造影检查。记录超声造影的动态变化。采用定量分析软件（QontraXt）分析肾皮质不同部位回声的时间-强度曲线。超声造影检查后，处死兔。分离肾皮质组织，提取组织 RNA 和总蛋白，分别采用实时 PCR 和 Western blot 检测 VEGF，采用 Pearson 积矩相关系数测量两者之间的线性关系。
超声对比能清楚地反映 IRI 过程。检测 mRNA 和蛋白水平的结果表明，IRI 组 VEGF 的表达明显增加（P < 0.05），再灌注时 VEGF 的表达也增加。
VEGF 的表达与 IRI 过程存在一定的相关性。AT 和 TTP 的超声对比参数与 VEGF 相对表达量的相关系数均在 0.9 以上，相关性较高。但各组灌注峰值强度的变化无差异，与 VEGF 表达无相关性。
