低剂量脂多糖对NIT-1β细胞凋亡、增殖和分泌功能的影响  

Effects of low-dose lipopolysaccharide on cell apoptosis, proliferation, and insulin secretion in NIT-1 β- cells

作　　者：梁绮君[1] 李焱[2] 刘珊英[2] 梁颖[2] 严励[2] 傅祖植[2] 

机构地区：[1]佛山市中医院糖尿病强化治疗中心,528000 [2]中山大学附属第二医院内分泌科

出　　处：《中华内分泌代谢杂志》2011年第9期761-765,共5页Chinese Journal of Endocrinology and Metabolism

基　　金：国家自然科学基金资助项目（30671974）;广东省自然科学基金资助项目（4009408、6021329）

摘　　要：目的观察脂多糖对小鼠胰岛NIT-1β细胞株凋亡、增殖和分泌功能的影响。方法以1μg／ml脂多糖孵育NIT-1细胞0～120h，Hochest33342和膜联蛋白V／碘化丙啶染色检测细胞凋亡，CCK-8（cell counting kit-8）和5-溴脱氧尿核苷（BrdU）检测细胞增殖，放射免疫法检测细胞内胰岛素含量、胰岛素基础分泌和葡萄糖刺激的胰岛素分泌（GSIS），Western印迹检测胰岛素受体底物2（IRS-2）的酪氨酸磷酸化水平。结果脂多糖作用120h对细胞凋亡无明显影响。脂多糖作用24、48h促进细胞增殖（P〈0．05或P〈0．01）；作用72h对细胞增殖无明显影响；作用96、120h抑制细胞增殖（均P〈0．01）。脂多糖作用48h以后明显抑制细胞的基础胰岛素分泌（均P〈0．01），对细胞内胰岛素含量和GSIS无明显影响。脂多糖作用120h，IRS-2的酪氨酸磷酸化水平明显下降（0．45±0．08对0．22±0．06，P〈0．05）。脂多糖作用60min后，NF—κB抑制物（IKBa）磷酸化水平开始明显升高；IκBα磷酸化抑制剂Bay11-7082预处理1h后，脂多糖刺激的IκBα磷酸化和细胞增殖均受抑制（均P〈0．01）。结论低剂量脂多糖参与调节NIT-1细胞的增殖和胰岛素基础分泌，其机制可能与其激活NF—κB和抑制IRS-2酪氨酸磷酸化有关。Objective To investigate the effects of lipopolysaccharide （LPS） on cell apoptosis, proliferation, and insulin secretion in a β-cell line, NIT-1. Methods NIT-1 cells were stimulated with 1 μg/ml LPS for 0-120 h. Cell apoptosis was evaluated by Hochest33342 staining and Annexin V/PI flow cytometry. Cell proliferation was evaluated by CCK-8 and BrdU assay. Intracellular insulin content, basal insulin secretion, and glucose-stimulated insulin secretion（GSIS） were detected by RIA. The IRS-2 tyrosine phosphorylation was determined by Western blot. Results Cell apoptosis was not significantly changed by treatment with LPS for 120 h. Cell proliferation was stimulated by LPS before 48 h, and inhibited after 96 h. Intracellular insulin content or GSIS was not altered, but basal insulin secretion was decreased significantly by LPS after 48 h （ all P〈0. 01 ）. LPS decreased the tyrosine phosphorylation level of IRS-2 （ 0. 45 ± 0. 08 vs 0. 22± 0. 06, P 〈 0. 05 ） and stimulated IκBα phosphorylation. Pretreatment with a specific IκBα phosphorylation inhibitor, Bayl 1-7082 for 1 h, remarkably blunted the LPS-induced phosphorylation of IκBα and cell proliferation （ both P〈0. 01 ）. Conclusions Low-dosages of LPS regulate proliferation and basal insulin secretion of NIT-1 β-cells, in which activation of NF-KB and inhibition of IRS- 2 tyrosine-phosphorylation may be involved.

关 键 词：脂多糖 NIT—1β细胞 凋亡 增殖 胰岛素分泌 

分 类 号：R587.1[医药卫生—内分泌]