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目的:探讨谷氨酰胺对经烧伤大鼠血清（以下简称烧伤血清）干预的大鼠心肌细胞的作用及其细胞信号机制。方法:采用实验研究方法。取10只7~8个月龄雌雄各半Wistar大鼠制备正常大鼠血清（以下简称正常血清），另取20只7~8个月龄雌雄各半Wistar大鼠造成30%体表总面积Ⅲ度烧伤后制备烧伤血清，从180只1~3 d龄雌雄不拘Wistar大鼠心尖组织中分离培养原代心肌细胞用于后续实验。按随机数字表法（分组方法下同）将细胞分为正常血清组、烧伤血清组，加入相应血清培养。分别于培养1、3、6、9、12 h，采用锥虫蓝实验检测细胞存活率。将细胞分为单纯烧伤血清组、烧伤血清+4 mmol/L谷氨酰胺组、烧伤血清+8 mmol/L谷氨酰胺组、烧伤血清+12 mmol/L谷氨酰胺组、烧伤血清+16 mmol/L谷氨酰胺组、烧伤血清+20 mmol/L谷氨酰胺组，采用单纯烧伤血清或烧伤血清+相应终物质的量浓度谷氨酰胺处理，培养前实验筛选出的干预时间，同前检测细胞存活率。将细胞分为正常血清组、单纯烧伤血清组、烧伤血清+12 mmol/L谷氨酰胺组、烧伤血清+16 mmol/L谷氨酰胺组、烧伤血清+20 mmol/L谷氨酰胺组，同前处理后采用蛋白质印迹法检测培养30 min哺乳动物雷帕霉素靶蛋白复合物1（mTORC1）、p70核糖体蛋白S6激酶（p70 S6K）和真核翻译起始因子4E结合蛋白1（4E-BP1）磷酸化水平。将细胞分为正常血清组、单纯烧伤血清组、烧伤血清+12 mmol/L谷氨酰胺组、烧伤血清+12 mmol/L谷氨酰胺+25 ng/mL雷帕霉素组，行相应处理后，分别于培养1、3、6 h，采用免疫荧光法检测热休克蛋白70（HSP70）和金属硫蛋白（MT）表达并观测微管形态。各组各时间点各指标样本数均为10。对数据行析因设计方差分析、单因素方差分析、LSD-n t检验、LSD检验及Bonferroni校正。n 结果:培养1、3、6、9、12 h，烧伤血清组细胞存活率均明显低于正常血清组（n t=4.950、16.752、35.484、34.428、27.781，n P0.05）。因此选择12、16、20 mmol/L作为后续谷氨酰胺的干预浓度。培养30 min，正常血清组、单纯烧伤血清组、烧伤血清+12 mmol/L谷氨酰胺组、烧伤血清+16 mmol/L谷氨酰胺组、烧伤血清+20 mmol/L谷氨酰胺组细胞mTORC1、p70 S6K、4E-BP1磷酸化水平分别为1.001±0.042、0.510±0.024、0.876±0.022、0.836±0.074、0.856±0.041，1.00±0.11、0.38±0.09、0.95±0.13、0.96±0.13、0.89±0.24，1.00±0.07、0.29±0.08、0.87±0.27、0.68±0.08、0.60±0.21。与正常血清组比较，其余4个烧伤血清组细胞mTORC1、p70 S6K、4E-BP1磷酸化水平均明显降低（n P0.05). Thus 12, 16, and 20 mmol/L were selected as the subsequent intervention concentrations of glutamine. After 30 min of culture, the phosphorylation levels of mTORC1, p70 S6K, and 4E-BP1 of cells were respectively 1.001±0.042, 0.510±0.024, 0.876±0.022, 0.836±0.074, 0.856±0.041, 1.00±0.11, 0.38±0.09, 0.95±0.13, 0.96±0.13, 0.89±0.24, 1.00±0.07, 0.29±0.08, 0.87±0.27, 0.68±0.08, 0.60±0.21 in normal serum group, burn serum alone group, burn serum+12 mmol/L glutamine group, burn serum+16 mmol/L glutamine group, and burn serum+20 mmol/L glutamine group. Compared with normal serum group, the phosphorylation levels of mTORC1, p70 S6K, and 4E-BP1 of cells were significantly decreased in the other 4 burn serum groups (n P<0.01). Compared with those of burn serum alone group, the phosphorylation levels of mTORC1, p70 S6K, and 4E-BP1 of cells were significantly increased in the other 3 burn serum groups (n P<0.01). The phosphorylation level of 4E-BP1 of cells in burn serum+12 mmol/L glutamine group was significantly higher than the levels in burn serum+16 mmol/L glutamine group and burn serum+20 mmol/L glutamine group (n P<0.05). The expression of MT of cells in burn serum alone group was significantly lower than that in normal serum group at PCH 1 (n P<0.05), while the expressions of MT of cells in burn serum alone group were significantly higher than those in normal serum group at the other time points (n P<0.05). At PCH 1, 3, and 6, the expressions of HSP70 of cells in burn serum alone group were significantly higher than those in normal serum group (n P<0.05), the expressions of HSP70 and MT of cells in burn serum+12 mmol/L glutamine group were significantly higher than those in burn serum alone group (n P<0.05), and the expressions of HSP70 and MT of cells in burn serum+12 mmol/L glutamine+25 ng/mL rapamycin group were significantly lower than those in burn serum+12 mmol/L glutamine group (n P<0.01). The microtubular structures were intact, displaying grid alinement and uniform staining in cells of normal serum group at PCH 1, 3, and 6. In burn serum alone group, some microtubules showed fracture and irregular grid arrangement at PCH 1; the microtubular structures near the nucleus were clear, while the microtubules at the distal end of the nucleus were blurry at PCH 3; the microtubular structures were blurry at PCH 6. The microtubular damage of cells was alleviated in burn serum+12 mmol/L glutamine group as compared with that in burn serum alone group at each time point of culture. The morphology of microtubules of cells in burn serum+12 mmol/L glutamine+25 ng/mL rapamycin group at each time point of culture was similar to that of burn serum alone group.n Conclusions:The burn serum can lead to damages to cardiomyocytes and significant decrease of cell survival rate in rats. Glutamine can exert cell protective function through the regulation of mTOR/p70 S6K/4E-BP1 signaling pathway, thus promoting the expressions of HSP70 and MT and stabilizing the microtubule structures.