COMPARATIVE STUDY OF PHOSPHOTYROSYL PROTEIN PHOSPHATASE OF MICE NORMAL LIVER, REGENERATING LIVER, AND MICE H22A HEPATOMA ASCITES CELL

In regenerating liver of mice, marked increase of the activity of phosphotyrosyl protein phosphatase (PTPP) in cytosol was observed. The PTPP activity varied with time and reached the highest level between 24 to 48 hours after partial hepatectomy. In H22a cells the PTPP activity found in every subcellular fraction was lower than that of the normal liver. The PTPP activity was mostly concentrated in lysosomes of normal liver, but mainly distributed in nucleus, cytosol and microsome of regenerating liver. In H22a cells PTPP activity seemed distribute evenly. Five similar major PTPP peaks (I-V) were obtained on DEAE cellulose chromatography of cytosols from all three of liver cells studied. However, two additional PTPP peaks, a and b, were also obtained from cytosol of liver.

小鼠正常肝、再生肝和腹水型肝癌H22a细胞酪氨酸蛋白磷酸酶的比较研究

小鼠肝在再生过程中,胞浆酪氨酸蛋白磷酸酶(PTPP)活力比正常肝有明显升高,并且伴有时相变化,,手术后24—48h活力达到最高,而H22a细胞各组分的活力都比正常肝低。PTPP在正常肝细胞的溶酶体中分布最高;再生肝中则在细胞核、胞浆和微粒体中更集中;在H22a细胞中,PTPP的活力分布趋于平均化。再生肝和H22a细胞胞浆中都缺少正常肝的a、b两个PTPP活力峰,其它五个主要PTPP峰与正常肝无根本的差别。

糖尿病小鼠来源的骨髓间充质干细胞培养上清液诱发胰岛素抵抗的研究

目的探究糖尿病小鼠来源的骨髓间充质干细胞及其旁分泌作用在诱发胰岛素抵抗(IR)中扮演的角色。方法建立小鼠糖尿病模型,提取并培养骨髓间充质干细胞(BMSC),收集培养上清液(M-BMSC-CS)。(1)细胞实验:将HepG2肝细胞分为正常低糖培养组[用低糖DMEM(5.55 mmol·L^(-1))进行培养]、M-BMSC-CS实验组(M-BMSC-CS 75μL)、高糖高脂对照组(给予25 mmol·L^(-1)高糖DMEM+0.25 mmol·L^(-1)棕榈酸)。(2)动物实验:小鼠分为正常小鼠组(腹腔注射等体积0.9%NaCl)和M-BMSC-CS-m组(M-BMSC-CS通过腹腔注射给予正常小鼠,注射剂量0.2 mL/10 g)。用葡萄糖氧化酶法检测葡萄糖摄取量,用免疫荧光法检测Glut2蛋白荧光强度,用蛋白质印迹法检测胰岛素信号通路蛋白表达;检测口服葡萄糖耐量(OGTT)和胰岛素耐量(ITT)。结果正常低糖培养组、M-BMSC-CS实验组和高糖高脂对照组的葡萄糖摄取量分别为(2.96±0.05)、(1.64±0.28)和(1.42±0.32)mmol·L^(-1),葡萄糖转运蛋白2(Glut2)荧光表达分别为53.21±2.70、30.95±3.39和34.96±7.60,磷酸化胰岛素受体底物1-ser307(p-IRS-1ser307)表达蛋白相对水平分别为0.46±0.21、1.09±0.24和0.91±0.16,磷酸化蛋白激酶(p-AKT)蛋白相对表达水平分别为0.94±0.05、0.59±0.06和0.53±0.05,Glut2蛋白表达水平分别为1.08±0.14、0.58±0.14和0.62±0.09;M-BMSC-CS实验组的上述指标与正常低糖培养组比较,在统计学上差异均有统计学意义(均P<0.05)。正常小鼠组和M-BMSC-CS-m组空腹血糖分别为(5.23±0.57)和(9.30±1.14)mmol·L^(-1),p-AKT蛋白相对表达水平分别为1.27±0.21和0.51±0.19,Glut2蛋白相对表达水平分别为1.17±0.17和0.79±0.09;M-BMSC-CS-m组的上述各指标与正常小鼠组比较,在统计学上差异均有统计学意义(均P<0.05)。结论糖尿病小鼠来源的BMSC培养上清液在体外引起正常HepG2肝细胞胰岛素抵抗,在体内诱发正常小鼠胰岛素抵抗。