發(fā)布時(shí)間：2018-05-24 05:56

  本文選題：2型糖尿病 + 胰島素抵抗　； 參考：《華中科技大學(xué)》2015年碩士論文

【摘要】：硒是哺乳動(dòng)物的一種必需微量元素。研究表明,硒具有類胰島素作用;而近來(lái)越來(lái)越多的研究表明,缺硒和硒過(guò)量會(huì)促進(jìn)糖尿病的發(fā)生發(fā)展,但內(nèi)在的機(jī)理仍然知之甚少。胰島素抵抗在2型糖尿病的發(fā)病機(jī)理中極其重要。因此,硒與胰島素抵抗之間關(guān)系的研究對(duì)深入了解硒與糖尿病的關(guān)系具有重要意義,對(duì)預(yù)防和治療2型糖尿病具有潛在的應(yīng)用價(jià)值。本文以亞硒酸鈉Na2SeO3處理的HepG2細(xì)胞為研究對(duì)象,研究了亞硒酸鈉對(duì)胰島素效應(yīng)與信號(hào)通路的影響及其機(jī)制,重點(diǎn)探討了高濃度亞硒酸鈉(1μM,2.5μM和5μM)對(duì)HepG2細(xì)胞的糖代謝(包括糖原合成和糖異生)、肝臟細(xì)胞中胰島素信號(hào)通路、氧化應(yīng)激水平、內(nèi)質(zhì)網(wǎng)應(yīng)激水平的影響,主要結(jié)果如下:我們采用糖原試劑盒、實(shí)時(shí)熒光定量PCR技術(shù)、蛋白質(zhì)印跡技術(shù)、分光光度法、活性氧試劑盒,研究了亞硒酸鈉對(duì)HepG2細(xì)胞胰島素信號(hào)通路的影響及可能的機(jī)制。結(jié)果表明,高濃度亞硒酸鈉使得HepG2細(xì)胞內(nèi)糖原含量降低,促進(jìn)了糖異生基因的表達(dá),降低了Akt的磷酸化水平。這說(shuō)明高濃度亞硒酸鈉導(dǎo)致胰島素敏感性降低,抑制胰島素信號(hào)傳導(dǎo),引起胰島素抵抗。亞硒酸鈉的加入沒(méi)有改變GRP78的表達(dá),說(shuō)明在HepG2細(xì)胞中,亞硒酸鈉可能不是或主要不是通過(guò)內(nèi)質(zhì)網(wǎng)應(yīng)激引起胰島素抵抗的。高硒處理使細(xì)胞中ROS含量增加,加入抗氧化劑N-乙酰半胱氨酸(N-acetylcysteine,NAC)可以降低高硒引起的ROS水平升高。NAC的加入可以逆轉(zhuǎn)由亞硒酸鈉導(dǎo)致的糖原合成減少和糖異生基因表達(dá)增加,這說(shuō)明亞硒酸鈉是通過(guò)ROS作用于胰島素信號(hào)通路的。同時(shí)NAC的加入使得Akt磷酸化水平升高,JNK磷酸化水平降低,IRS1酪氨酸磷酸化水平升高,說(shuō)明ROS的減少能夠增強(qiáng)胰島素信號(hào),ROS通過(guò)激活JNK而導(dǎo)致IRS1酪氨酸磷酸化降低而抑制胰島素信號(hào)轉(zhuǎn)導(dǎo),引起胰島素抵抗,抑制糖原合成,促進(jìn)糖異生。我們的實(shí)驗(yàn)結(jié)果表明,亞硒酸鈉通過(guò)誘導(dǎo)HepG2細(xì)胞中產(chǎn)生ROS,激活JNK,通過(guò)抑制IRS1的酪氨酸磷酸化而抑制胰島素信號(hào)轉(zhuǎn)導(dǎo),引起胰島素抵抗。
[Abstract]:Selenium is an essential trace element in mammals. Studies have shown that selenium has insulin-like effects, and more recent studies have shown that selenium deficiency and excess selenium can promote the development of diabetes, but the underlying mechanism is still poorly understood. Insulin resistance is very important in the pathogenesis of type 2 diabetes. Therefore, the study on the relationship between selenium and insulin resistance is of great significance in understanding the relationship between selenium and diabetes mellitus, and has potential application value in the prevention and treatment of type 2 diabetes mellitus. The effect of sodium selenite on insulin effect and signal pathway and its mechanism were studied in HepG2 cells treated with sodium selenite Na2SeO3. The effects of high concentration of sodium selenite (1 渭 M, 2.5 渭 M and 5 渭 M) on glucose metabolism (including glycogen synthesis and glycosylation, insulin signaling pathway, oxidative stress level, endoplasmic reticulum stress level) in HepG2 cells were studied. The main results are as follows: the effects of sodium selenite on insulin signaling pathway in HepG2 cells were studied by using glycogen kit real-time fluorescence quantitative PCR Western blot spectrophotometry and reactive oxygen species kit. The results showed that high concentration of sodium selenite reduced the content of glycogen in HepG2 cells, promoted the expression of glycosylated allogenes and reduced the phosphorylation level of Akt. This suggests that high concentration of sodium selenite leads to decrease of insulin sensitivity, inhibition of insulin signal transduction and insulin resistance. The addition of sodium selenite did not change the expression of GRP78, suggesting that sodium selenite may not or mainly not induce insulin resistance in HepG2 cells through endoplasmic reticulum stress. High selenium treatment increased the content of ROS in the cells. The addition of the antioxidant N-acetylcysteine NACcould reduce the increase of ROS level induced by high selenium. The addition of NAC could reverse the decrease of glycogen synthesis induced by sodium selenite and the increase of glycosylcysteine gene expression. This suggests that sodium selenite acts on the insulin signaling pathway through ROS. At the same time, the addition of NAC increased the level of Akt phosphorylation and decreased the level of tyrosine phosphorylation of IRS1. It is suggested that the decrease of ROS can enhance the insulin signal. Ros can inhibit the insulin signal transduction by activating JNK and leading to the decrease of IRS1 tyrosine phosphorylation, which can induce insulin resistance, inhibit glycogen synthesis and promote glycosylation. Our results show that sodium selenite induces ROS in HepG2 cells, activates IRS1 and inhibits insulin signal transduction and insulin resistance by inhibiting tyrosine phosphorylation of IRS1.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：R587.1

【參考文獻(xiàn)】

相關(guān)期刊論文 前7條

1 任春久;張瑤;崔為正;牟志美;;氧化應(yīng)激在2型糖尿病發(fā)病機(jī)制中的作用研究進(jìn)展[J];生理學(xué)報(bào);2013年06期

2 周軍;白兆帥;徐輝碧;黃開(kāi)勛;;硒蛋白與糖尿病——硒的兩面性[J];化學(xué)進(jìn)展;2013年04期

3 孫慶磊;高宏凱;張新國(guó);;肝細(xì)胞胰島素信號(hào)傳導(dǎo)通路與胰島素抵抗[J];中國(guó)實(shí)用醫(yī)藥;2007年33期

4 高良才,陳婉蓉,吳麗萍,倪周利,張寶君;硒對(duì)肝臟腦體外脂質(zhì)過(guò)氧化的影響[J];微量元素與健康研究;2001年02期

5 朱玉山,黃開(kāi)勛,徐輝碧;硒化合物的擬胰島素作用[J];生命的化學(xué);2001年01期

6 戴麗梅,阮兆晶,馬長(zhǎng)華,姜國(guó)財(cái),包亞?wèn)|,吳煥得,董慶;硒鋅聯(lián)合應(yīng)用對(duì)奶�？寡趸�功能的影響[J];中國(guó)獸醫(yī)雜志;1999年07期

7 楊萍,劉昕;亞硒酸鈉抗氧化作用與抑瘤效應(yīng)的實(shí)驗(yàn)觀察[J];中國(guó)腫瘤生物治療雜志;1998年01期

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