曲格列酮上调PPARγ抑制炎症状态下小胶质细胞iNOS表达的实验研究

Troglitazone reduces the expression of iNOS via up-regulation of PPARγ in BV2 microglia

目的探讨曲格列酮能否通过上调PPARγ抑制炎症状态下小胶质细胞iNOS表达,以及对细胞的保护作用。方法将BV2细胞分为4组,即对照组(Control组)、LPS组、LPS+曲格列酮组(LPS+Troglitazone组,LPS+Tro组)和LPS+曲格列酮+GW9662组(LPS+Troglitazone+GW9662组,LPS+Tro+GW组),使用MTT法在0、24h对BV2细胞活性进行观察,并在干预24小时后使用RT-PCR法和western blot法对BV2细胞iNOS和PPARγmRNA和蛋白的表达水平进行检测。结果在给予LPS干预24小时后BV2细胞活性明显降低,差异均有统计学意义(均P<0.05);LPS+Tro组细胞活性较LPS组和LPS+Tro+GW组更高,差异均有统计学意义(均P<0.05);同时LPS组和LPS+Tro+GW组细胞活性差异未见统计学意义(P>0.05)。在给予LPS干预24小时后BV2细胞iNOS mRNA和蛋白的表达水平较Control组细胞明显增加,PPARγmRNA和蛋白的表达水平较Control组细胞明显下降,差异均有统计学意义(均P<0.05);同时LPS+Tro组细胞一氧化氮合成酶(iNOS)表达水平较LPS组和LPS+Tro+GW组降低,而PPARγ表达水平较LPS组和LPS+Tro+GW组升高,差异均有统计学意义(均P<0.05);同时LPS组和LPS+Tro+GW组细胞间iNOS和PPARγ表达水平差异未见统计学意义(均P>0.05)。结论本实验结果表明,在LPS诱导的炎症状态下,曲格列酮可以通过促进PPARγ的表达下调BV2细胞iNOS的合成,并对BV2细胞具有保护作用。

Objective To investigate whether PPARγ agonist troglitazone would inhibit iNOS expression via upregulation of PPARγ in BV2 mieroglia in LPS induced inflammation. Methods MTT was used to measure the cell viabilities at Oh and 24h. RT-PCR and western blot were included to measure the mRNA and protein expression of iNOS and PPARγ, respectively. Results After 24 hours LPS stimulation, the cell viabilities of BV2 microglia was largely reduced, However, troglitazone improved the LPS-reduced ceil viability, and this effect of troglitazone was noticeably blocked by GW9662. Meanwhile, the LPS-induced over-expression of iNOS were significantly reduced, and, the LPS-induced down- regulation of PPARγ were remarkably increased by troglitazone intervention in BV2 microglia. Additionally, these effects of troglitazone were markedly abrogated by PPAR7 antagonist GW9662. Conclusion PPAR7 agonist troglitazone could inhibit the expression of iNOS through the up-regulation of PPARγ in BV2 microglia in LPS induced inflammation.