内源性二氧化硫及其生成酶在大鼠体内的生成与分布

目的：探讨内源性二氧化硫(SO2)及其生成酶谷氨酸草酰乙酸转移酶(GOT)在大鼠体内的正常分布。 方法：选用Wistar大鼠，分别留取心、肝、肺、肾、主动脉、肺动脉、肠系膜动脉、肾动脉和尾动脉，应用高效液相色谱荧光法(HPLC)检测各组织中亚硫酸盐的含量；应用酶学法测定各组织中GOT酶活性及荧光定量PCR测定各组织中GOT mRNA的含量；原位杂交检测血管组织中GOT mRNA的分布。结果：心、肝、肺、肾、主动脉、肺动脉、肠系膜动脉、肾动脉和尾动脉中均含有一定量的亚硫酸盐，且以动脉血管中的含量较高；心、肝、肾等组织中的GOT酶活性及GOT mRNA含量明显高于动脉血管的含量；GOT mRNA主要位于血管内皮细胞和近内皮的血管平滑肌细胞。结论：SO2可在心血管系统内源性产生，动脉血管中SO2含量高于组织器官中的含量，GOT酶及GOT mRNA的含量在动脉血管中较低，这可能与局部代谢及作用有关。

Production and distribution of endogenous sulfur dioxide and its generating enzyme in rats

AIM:To investigate the distribution of endogenous sulfur dioxide (SO2) and its generating enzyme (glutamate oxaloacetate transaminase, GOT) in normal rats. METHODS: Wistar rats were anaesthetized and heart, liver, lung, kidney and vascular tissues (including aorta and pulmonary, mesenteric, kidney and tail arteries) were isolated rapidly. SO2 content was determined by reverse-phase HPLC with fluorescence detection and GOT was detected in various tissues by quantitative real-time RT-PCR and enzymatic methods. GOT mRNA expression in arteries was studied through in situ hybridization. RESULTS: SO2 was endogenously generated in various rat tissues, including heart, liver, lung, kidney and arteries. The SO2 content was higher in arteries than that in other tissues. GOT enzyme and GOT mRNA expression were higher in heart, liver and kidney than those in arteries, and GOT1/GOT2 mRNA located in endothelia and vascular smooth muscle cells near endothelial layer. CONCLUSION: SO2 is endogenously generated in cardiovascular system, and the SO2 content in arteries is higher than that in other organs. GOT enzyme and GOT mRNA expression are low in arteries, and this phenomenon may be related with local metabolism.