游离脂肪酸诱导肾小管上皮细胞凋亡的实验研究

目的 探讨游离脂肪酸（FFAs）对大鼠近端肾小管上皮细胞（NRK-52E）的凋亡作用及凋亡机制。方法 用含有不同浓度（0、125、250、500μM）软脂酸的DMEM-F12培养肾小管上皮细胞（NRK-52E）,在24h、48h两个时段以原位末端标记（TUNEL法）检测细胞凋亡率,用硝酸还原酶法测定以上各组培养液中一氧化氮（NO）水平。在48h时段用免疫细胞化学法检测caspase-3表达水平。结果 随着软脂酸浓度的增高、作用时间的延长：①NRK-52E细胞的凋亡率逐渐增高,24h时三个软脂酸组按软脂酸浓度由低到高的凋亡率依次为（9.7±1.9）%、（14.2±4.5）%、（23.4±5.3）%,48h时为（16.2±3.7）%、（24.8±4.4）%、（35.4±5.7）%,与对照组相比均有统计学意义（P〈0.05）;②在凋亡率增高组的培养液中测得NO浓度也增加,差异均有显著性（P〈0.05）。③48h时各软脂酸干预组caspase-3阳性表达率增高,与对照组相比均有统计学差异（P〈0.05）。结论 游离脂肪酸具有促进肾小管上皮细胞凋亡的作用,而这种作用与其自身在FFAs作用下产生过多的NO使caspase-3高表达有关。

Free Fatty Acid-induced Apoptosis of Renal Tubular Epithelial Cells:An Experimental Study

Objective To observe the effect and mechanism of free fatty acid （FFAs）on apoptosis of proximal renal tubular epithelial cells. Methods Rat renal tubular epithelial cells（NRK-52E） were cultured with DMEM-F12 at different concentrations of palmitic acid （0,125,250 and 500uM）at 24h and 48h,respectively. The percentage of apoptotlc cells was assessed by Tunel and Nitrate reduction test was used to measure NO content of the medium. Caspase-3 expression was detected by immunocytochemistry method at 48h. Results As the palmitic acid concentration increased and the reactive time prolonged, the apoptosis rate of NRK-52E cells was gradually increased, at 24 h the apoptosis rates of the three palmitic acid groups at the concentrations of palmitic acid from low to high were（9.7 ± 1.9）%, （14.2 ± 4.5 ）% and （ 23.4 ± 5.3 ）%, at 48h（ 16.2 ± 3.7 ）%, （24.8 ± 4.4）%, （ 35.4 ± 5.7 ） % and they were significantly different from the apoptosis rate of the control group（P〈0.05）. The NO concentration was also increased in the culture medium in the increased apoptosis rate group,with a significant difference（P〈0.05）. The caspase-3 positive expression rate was increased in the palmitie acid intervention groups at 48h, with a significant differenee（P〈0.05 ）. Conclusion Free fatty acid is capable of inducing rat proximal renal tubular epithelial cell apoptosis, Which is closely related to the high expression of caspase-3caused by the excess NO generated with the FFAs effect on it.