Exendin-4对抵抗素介导的βTC6细胞PDX-1表达损害及细胞凋亡的干预作用

The Effect of Exendin-4 on the Resistin-induced PDX-1 Expression Impairment and Cell Apoptosis in βTC6 Cells

目的研究Exendin-4是否能拮抗抵抗素对胰岛βTC6细胞的毒性作用。方法βTC6细胞分为对照组、抵抗素（200ng/mL）干预组和Exendin-4干预组（浓度5、10、50nmol/L＋抵抗素200ng/mL）,分别干预6、12、24h。CCK-8法测定细胞增殖能力,DNA Ladder检测细胞凋亡,RT-PCR检测PDX-1基因表达,放射免疫法测定胰岛素分泌。结果 （1）与抵抗素干预组比较,Exendin-4低浓度（5nmol/L）和短时间（6h）未改善βTC6细胞的胰岛素分泌能力和增殖能力（P〉0.05）,且未减轻细胞凋亡;适宜浓度（10∽50nmol/L）及干预时间的延长（12、24h）均明显改善βTC6细胞的胰岛素分泌能力和增殖能力（P〈0.05）,10nmol/L和50nmol/L浓度组间差别无统计学意义（P〉0.05）,延长至24h时2种浓度组均可明显减少细胞凋亡;（2）Exendin-4预干预6h,各组βTC6细胞的PDX-1表达未见明显改变;当干预时间延长,各浓度组的PDX-1表达逐渐增加,10nmol/L和50nmol/L浓度组间差别无统计学意义（P〉0.05）。结论在一定干预时间和浓度范围内,Exendin-4可增加抵抗素作用下βTC6细胞PDX-1mRNA的表达,增加胰岛素分泌和增殖能力,减轻细胞凋亡。

Objective To investigate whether Exendin‐4 has antagonism against resistin’s cyto‐toxicity onβcell . Methods βTC6 cells were divided into control group ,resistin group （200 ng/mL） and Exendin‐4 group （5 ,10 ,50 nmol/L＋resistin 200 ng/mL respectively） ,and intervened for 6 ,12 and 24 h . The cell proliferation ability was examined by CKK‐8 . Cell apoptosis rate was detected by DNA laddering assay . The mRNA of PDX‐1 was examined by reverse transcription polymerase chain reaction （RT‐PCR） . And insulin secretion （IS） was observed in every group by radioimmunoassay . ResuIts （1） Compared with resistin group ,low concentration（5 nmol/L） and short term intervention（6 h） of Exendin‐4＆amp;nbsp;did not improveβTC6 insulin secretion ,cell proliferation（P〉0 .05） ,and apoptosis . Appropriate concen‐tration（10∽50 nmol/L） and longer pre‐intervention time （12 ,24 h） of Exendin‐4 can significantly improveβTC6 cell insulin secretion and proliferation （ P〈 0 .05） . No significant difference was found between these two concentration groups（P〉0 .05） and 24 h‐intervention in these two concentration groups can sig‐nificantly reduce apoptosis . （2 ） There was no significant change in PDX‐1 expression among each Exendin‐4 concentration group if the pre‐intervention time was 6 h . However ,various increasing expres‐sion of PDX‐1 was detected when the pre‐intervention time increased and no significant difference was found between 10 nmol/L group and 50 nmol/L group （P〉0 .05） . ConcIusion Exendin‐4 in a certain range of concentration may show a time‐and concentration‐dependent manner of up‐regulating gene expres‐sion of PDX‐1 against resistin‐induced cytotoxicity ,improving insulin secretion function ,proliferation and apoptosis inβcells .