血管周围脂肪组织在肾性高血压中的作用

The function of perivascular adipose tissue in renal hypertension

目的探讨血管周围脂肪组织(PVAT)在肾性高血压发生、发展中的的作用。方法用两肾一夹型(左侧肾动脉狭窄,右侧肾保留)建立肾性高血压大鼠模型,将20只SD大鼠随机均分为假手术组和肾性高血压组(RH),术前及术后8周末检测大鼠尾动脉血压、心率,术后8周检测动脉环不带血管外周脂肪组织的裸血管环[F(-)]和保留血管外周脂肪组织的血管环[F(+)]对苯肾上腺素(PHE)及乙酰胆碱的反应性;免疫组化法检测一氧化氮合酶(NOS)的表达;光镜下观察PVAT中脂肪细胞和血管结构,并计算脂肪细胞的体积、胸主动脉中层壁厚(MT)、血管内径(LD)及MT/LD。结果假手术组和RH组中带有脂肪的与无脂肪的胸主动脉比较,前者对PHE的收缩反应下降(P<0.05),而假手术组对乙酰胆碱的舒张反应,在浓度为10-5mol/L和10-4mol/L上,F(+)和F(-)差异有统计学意义(P<0.05),F(+)舒张反应性较F(-)高;RH组只有在10-4mol/L浓度上,F(+)较F(-)舒张反应性高(P<0.05)。RH组的血管NOS表达较假手术组降低。PVAT中脂肪细胞形态与大小、两组的动脉结构无明显区别。结论 PVAT对血管舒缩有调节功能;在RH组PVAT这种调节作用减弱;PVAT可能成为干预高血压的新靶点。

Objective To investigate the roles of the perivascular adipose tissue （PVAT） in renal hypertension. Methods Renal hypertension rat mode was established with two kidney one clip （2K1C） technique. Twenty SD rats were randomly divided equally into sham group （SH） and renal hypertension group （RH）. Vasomotoricity of aorta with PVAT or without PVAT from the 2 groups of rats in response to phenylephrine （PHE） and aeetylcholine （Ach） was tested after model established for 8 weeks. The expression of NOS was assayed by immunohistochemistry. Caudal arterial blood pressure, heart rate （ HR）, microscopic changes in adipose ceils and vascular structure and intima media thickness （MT）, lumen diameter （LD） and ratio of media thickness to lumen diameter （MT/LD） of thoracic aorta were evaluated in all rats. Results Contraction of aorta from the 2 groups of rats in response to PHE was significantly attenuated by the presence of PVAT（P〈0. 05 ）. Relaxation of aorta from SH group in response to Ach .（ 10-5 and 10 4 mol/L） was significantly increased in the presence of PVAT. But only in the concentration of 10^-4 mol/L, relaxation of aorta from RH group showed significant increase in response to Aeh in the presence of PVAT （P〈0.05）. NOS expression in aorta was higher in SH group than in RH group. Microscopic changes in adipose cells and vascular structure were no significantly different in the two groups. Conclusion PVAT could regulate vasomotoricity in SD rats, which is attenuated in the renal hypertension.