目的：血管紧张素转化酶抑制剂(ACEI)能降低先天性心脏病患儿肺循环与体循环血流量比值,减少左向右分流,推测这些患儿体、肺循环血管紧张素(Angiotensin,Ang)Ⅱ受体表达存在差异。该研究探讨左向右分流先天性心脏病患儿体、肺循环1型和2型血管紧张素Ⅱ受体(AT1,AT2)表达的差异。方法：20例左向右分流先天性心脏病患儿术中取肺、骨骼肌活检。用免疫组化的方法进行AT1,AT2受体染色。利用图像分析技术测定管径为15～100μm的肺、骨骼肌、胸膜小血管壁AT1、AT2染色的染色强度(IOD值)。结果：先天性心脏病患儿肺小血管AT1,AT2受体染色的染色强度为(124±95)×103,(85±62)×103均弱于同管径的骨骼肌(219±156)×103,(155±139)×103和胸膜小血管壁(279±191)×103,(175±128)×103(均P<0.05)。骨骼肌和胸膜血管AT1,AT2受体的表达差异无显著性。结论：左向右分流先天性心脏病患儿体循环小血管AT1,AT2受体的表达高于肺循环。

OBJECTIVE: It has been shown that angiotensin converting enzyme inhibitors (ACEI) can reduce the ratio of pulmonary and systemic circulation blood flow (Qp/Qs) and thus decrease the blood flow of left-to-right shunt in children with left-to-right shunt congenital cardiac lesions. This suggests that there are differences in the expression of Angiotensin Ⅱ receptors between systemic and pulmonary circulation. This study aimed to explore the differences of Angiotensin Ⅱ receptors type 1 and type 2 (AT1 and AT2 receptors) expression between systemic and pulmonary circulation in children with left-to-right shunt congenital cardiac lesions. METHODS: Lung and skeletal muscular tissues were obtained from 20 children with left-to-right shunt congenital cardiac lesions by biopsy during operation. The specimens were stained by immunohistochemistry techniques for AT1 and AT2 receptors. The technique of morphometric analysis was used to measure the immunoreactivity of AT1 and AT2 receptors (expressed by IOD values) of pulmonary, skeletal muscular and pleural small vascular wall the diameter of which was 15-100 μm. RESULTS: The immunoreactivities of AT1 and AT2 receptors of pulmonary small vascular walls [(124±95)×103 and (85±62)×103 respectively] were significantly lower than those of skeletal muscular [(219±156)×103 and (155±139)×103 respectively] and those of pleural small vascular walls [(279±191)×103 and (175±128)×103 respectively] in children with left-to-right shunt congenital cardiac lesions (P<0.05). CONCLUSIONS: The expression of AT1 and AT2 receptors in small vascular walls of systemic circulation was higher than that of pulmonary circulation in children with left-to-right shunt congenital cardiac lesions.