Insulin-like growth factor-1 inhibits apoptosis of rat gastric smooth muscle cells under high glucose condition via adenosine monophosphate-activated protein kinase (AMPK) pathway.
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引用次数: 2
Abstract
Introduction: Diabetic gastroparesis (DGP) is a common chronic complication of diabetes characterized by decreased gastric motility, and an effective number of gastric smooth muscle cells (GSMCs) ensures gastric motility. A previous study documented that apoptosis was present in gastric smooth muscles in rats with DGP and adenosine monophosphate-activated protein kinase (AMPK) was an important factor of apoptosis of rat GSMCs cultured under high glucose conditions. This study aimed to explore the effect of insulin-like growth factor-1 (IGF-1) on apoptosis of high glucose cultured rat GSMCs after silencing of AMPK and elucidate the underlying mechanism.
Material and methods: A total of 120 rats were divided into normal control (NC, n = 20), diabetic gastroparesis (DGP, n = 50) and DGP + IGF-1 (n = 50) groups. After establishing the rat model of DGP, rats in the DGP+IGF-1 group received an intraperitoneal injection of IGF-1 at a dose of 1.5 μg/kg/d for 10 weeks. The level of AMPK activity, liver kinase B1 (LKB1) activity, and calcium/calmodulin-dependent protein kinase b (CaMKKb) expression in rat gastric smooth muscle tissues was detected by Western blot analysis. Apoptosis in rat gastric smooth muscle tissues was detected by TUNEL assay. We also cultured rat GSMCs in vitro under high glucose (HG) condition (35 mM), incubated cells with IGF-1, and silenced AMPK with siRNA. The cells were divided into HG, HG + IGF-1, HG + siRNA, and HG + siRNA + IGF-1 groups. The apoptosis rates of rat GSMCs after silencing AMPK were detected by TUNEL assay and flow cytometry, and apoptosis-related protein expression in rat GSMCs was detected by Western blot.
Results: IGF-1 decreased LKB1 activity, CaMKKb expression, AMPK activity, and inhibited apoptosis in rat gastric smooth muscle tissues. Compared with rat GSMCs cultured in vitro under HG conditions, apoptosis rates were reduced after treatment with IGF-1 and AMPK silencing (both p < 0.01). Apoptosis rates were higher in the HG + siRNA group compared with the HG + IGF-1 group (p < 0.05). IGF-1 down-regulated the expression of calcium/calmodulin-dependent kinase II (CaMKII) and p53, up-regulated the expression of p21, PLC-b3, PI3K p110 Ser1070, and the activities of Akt, p70S6K, mTORC1, and mTORC2. IGF-1 also up-regulated Bcl-2 expression and down-regulated the expression of BAX and Caspase-3.
Conclusions: IGF-1 can inhibit the apoptosis of rat GSMCs under high glucose conditions, its mechanism may be related to the regulation of expression and activity of p53, PI3K, TSC-2, Akt, mTOR, 4E-BP1, p70S6K, p21, CaMKII, and PLC-b3 in rat GSMCs acting through AMPK pathway.
期刊介绍：
Accounts of Chemical Research presents short, concise and critical articles offering easy-to-read overviews of basic research and applications in all areas of chemistry and biochemistry. These short reviews focus on research from the author’s own laboratory and are designed to teach the reader about a research project. In addition, Accounts of Chemical Research publishes commentaries that give an informed opinion on a current research problem. Special Issues online are devoted to a single topic of unusual activity and significance.
Accounts of Chemical Research replaces the traditional article abstract with an article "Conspectus." These entries synopsize the research affording the reader a closer look at the content and significance of an article. Through this provision of a more detailed description of the article contents, the Conspectus enhances the article's discoverability by search engines and the exposure for the research.
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