视黄醇结合蛋白的促胆固醇成核效应

Cholesterol nucleation-promoting potency of retinol binding protein

目的检测视黄醇结合蛋白（RBP）在体外模拟胆汁体系中的促胆固醇成核作用，观察胆固醇成核及结晶过程。方法构建Small和综合模拟胆汁体系。于Small模拟胆汁中分别加入RBP（RBP组）、α1-酸性糖蛋白（AAG，AAG组）和Alb（Alb组），运用Busch法测定成核时间指数、结晶生长速度指数和结晶最终浓度指数。于Small和综合模拟胆汁中分别加入Alb（对照组）和RBP（实验组），采用Holan法测定成核时间、Holzbach法计算成核活性，并于光镜下观察胆固醇成核、结晶的形态学动态变化过程。两两比较采用t检验，多组比较采用方差分析。结果AAG组成核时间指数为0．66，结晶生长速度指数为1．29，结晶最终浓度指数为1．01。RBP组成核时间指数为0．73，结晶生长速度指数为1．02，结晶最终浓度指数为0．95。Small模拟胆汁体系中，对照组的平均成核时间为（12．2±1．2）d，实验组为（8．2±1．5）d，两组比较，差异有统计学意义（t=2．97，P〈0．05）。RBP在Small模拟胆汁体系中成核活性为0．67。综合模拟胆汁体系中，对照组的平均成核时间为（9．5±1．1）d，实验组为（7．5±1．1）d，两组比较，差异有统计学意义（t=2．35，P〈0．05）。RBP在综合模拟胆汁体系中的成核活性为0．79。胆固醇成核、结晶过程分为4个阶段。第2l天时整个胆汁体系中出现分割现象。结论RBP在体外模拟胆汁体系中具有促成核活性。

Objective To detect the nucleation-promoting potency of retinol binding protein （RBP） inthe simulated bile system, and observe the process of cholesterol nucleation and crystallization. Methods Small and synthetic bile systems were synthesized. RBP （RBP group）, α1-acid glycoprotein （AAG, AAG group） and albumin （Alb, Alb group） were added into the Small bile respectively. The derived indices of nucleation time, crystal growth rate and final concentration of crystal were studied by Busch method. Alb （control group） and RBP （experimental group） were added into the Small and synthetic bile systems respectively. The nucleation time was detected by polarizing microscopy according to the Holan method and the nucleation-promoting potency was calculated according to the Holzbach method. The morphological dynamics of cholesterol nucleation and crystallization were observed under a light microscope. All data were analyzed by using the analysis of variance or the t test. Results The derived indices of nucleation time, crystal growth rate and final concentration of crystal were 0.66, 1.29 and 1.01 in the AAG group, and 0.73, 1.02, 0.95 in the RBP group, respectively. In the Small bile system, the average nucleation time of cholesterol monohydrate crystals were （12.2 ± 1.2）days in the control group and （ 8.2 ± 1.5 ） days in the experimental group, respectively, with a significant difference between the 2 groups （t= 2. 97, P 〈 0.05 ）. The nucleation activity of RBP was 0.67 in the Small bile system. In the synthetic bile system, the average nucleation time of cholesterol monohydrate crystals were （9.5 ±1.1 ） days in the control group and （ 7.5 ± 1. 1 ） days in the experimental group, respectively, with a significant difference between the 2 groups （ t = 2. 35, P 〈 0.05 ）. The nucleation activity of RBP was 0. 79 in the synthetic bile system. The process of cholesterol nucleation and crystallization was divided into 4 stages, and the split phenomenon appeared in the bile system at day 21. Conclusion RBP is a pro-nucleation factor in simulated bile system.