高渗和低渗造影剂对鼠的肾毒性及福辛普利或替米沙坦的保护作用

目的:比较高渗造影剂和低渗造影剂的肾毒性,探讨福辛普利或替米沙坦对造影剂肾毒性是否有保护作用及其可能的作用机制.方法:健康纯系SD大鼠48只,雌雄各半,随机分为正常对照组、甘油对照组、高渗造影剂组(HOCM)、低渗造影剂组(LOCM)、福辛普利预防组及替米沙坦预防组.除正常对照组外,其余组以25%高渗甘油盐水10 mL/kg后腿肌肉注射,诱导甘油肾损害模型.福辛普利或替米沙坦预防组在注射造影剂前1 h分别予以福辛普利10 mg/kg或替米沙坦5 mg/kg灌胃.注射造影剂后48 h处死大鼠,采用自动生化分析仪检测血清肌酐(SCr)水平,采用放射免疫法测定血浆血管紧张素Ⅱ(AngⅡ)水平.取左肾下极肾脏组织匀浆,采用比色法测肾组织中caspase-3活性;另取右肾下极肾组织,采用HE染色观察肾组织病理损害;采用免疫组织化学法检测肾组织claudin-1蛋白的表达;采用TUNEL染色检测肾小管上皮细胞凋亡.结果:注射造影剂后48 h,高渗和低渗造影剂均可引起肾鲻小管上皮细胞凋亡,HOCM组凋亡率明显高于LOCM;与对照组和LOCM组比较,HOCM组血清SCr和血浆AngⅡ水平明显增高,肾组织claudin-1蛋白的表达和caspase-3酶活性上调;福辛普利或替米沙坦预防组SCr和AngⅡ水平明显降低,肾组织claudin-1蛋白的表达和caspase-3酶的活性明显下调,肾组织损害减轻,肾小管上皮细胞凋亡率明显降低.结论:HOCM及LOCM均可诱导肾小管上皮细胞凋亡,且HOCM的作用更强.其机制可能与高渗造影剂上调caspase-3活性和claudin-1蛋白表达及AngⅡ水平增高有关;福辛普利或替米沙坦对造影剂肾毒性有一定保护作用.

Nephrotoxicity of high- and low-osmolar contrast media:Protective role of forsinopril or telmisartan in a rat model

OBJECTIVE: To compare the nephrotoxicity of high- and low-osmolar contrast media (HOCM and LOCM), and to determine the protective role of forsinopril or telmisartan and its possible mechanism. METHODS: Forty eight healthy SD rats were randomly divided into 6 groups: a normal control group, a glycerol control group, a low-osmolar contrast media (LOCM) group, a high-osmolar contrast media (HOCM) group, a forsinopril group, and a telmisartan group. Glycerine for inducing kidney damage was given to all rats except the normal control group. Twenty-four hours after the injection of glycerine, the mixed forsinopril suspension (10mg/kg) or telmisartan (5mg/kg) was poured into the stomach in the preventive group. Serum creatinine (SCr) and plasm angiotensin II (AngII) levels were detected by an automatical biochemical analyzer and radioimmunoassay; caspase-3 activity and claudin-1 expression of the renal tissue were detected by fluorometric method and immunohistochemical method. The renal injury was assessed by hematoxylin and eosin (HE) staining and terminal deoxynucleotide mediated nick and labeling (TUNEL) staining, respectively. RESULTS: In diatrizoate-injected rats, SCr and AngII levels were increased (P<0.05). Expression of claudin-1 protein and caspase-3 activity in the renal tissue was upregulated. The histologic changes and percentage of apoptotic cells were milder in the LOCM rats than those in the HOCM rats. In the group pretreated with forsinopril or telmisartan, no increase in the levels of SCr and AngII was discovered. The expression of claudin-1 protein and caspase-3 activity was significantly lower than that in the HOCM group. The renal injuries induced by diatrizoate were alleviated. CONCLUSION: Both HOCM and LOCM could cause cellular apoptosis in the kidney.LOCM was less toxic to rat kidney than HOCM. Nephrotoxicity induced by HOCM might be related to caspase-3, claudin-1 and AngII. Forsinopril or telmisartan may protect the renal tissue from nephrotoxicity induced by diatrizoate.