赖氨酸摄入量对大鼠血浆免疫球蛋白G合成动力学参数的影响

EFFECT OF LYSINE INTAKES ON SYNTHESIS KINETIC PARAMETERS OF PLASMA IMMUNOGLUBULIN G IN RATS

目的用重水(2H2O)作为示踪剂标记大鼠血浆免疫球蛋白G(IgG),测定赖氨酸摄入量对大鼠血浆IgG合成动力学参数的影响。方法健康成年雄性SD大鼠60只随机分为3组,分别给予低(0.2%)、正常(0.9%)和高赖氨酸(1.6%)饲料喂养18w。从第9w开始,用2H2O标记大鼠至实验结束。分别在第9、11、13、14、18w末处死大鼠,检测血浆IgG、赖氨酸含量,将血浆IgG纯化、鉴定、水解、衍生,检测衍生物中的2H-丙氨酰基和血浆游离丙氨酸中2H的丰度。计算IgG的分数合成率(FSR)和合成动力学方程。结果在低、正常、高赖氨酸摄入状态下,大鼠血浆IgG的分数合成率分别为:8.82%/w、17.87%/w、24.77%/w,对应的合成动力学方程为:ft=0.1116×(1-e^0.0882t)、ft=0.0781×(1-e^-0.1787t)、ft=0.0741×(1-e^-0.2477t),赖氨酸摄入量与IgG的FSR之间相关系数r=0.99。结论赖氨酸摄入量与大鼠血浆IgG的FSR成正相关关系。

Objective To determine the effect of lysine intakes on synthesis kinetic parameters of plasma immunoglobulin G (IgG) in rats by heavy water ( 2H2O). Methods Sixty healthy adult male Sprague-Dawley rats were randomly divided into 3 groups. Their diets provided low (0.2%), normal (0.9%) and high lysine (1.6%) diets, respectively. By the 9th week, the rats were labeled with 2H2O until the end of the study. At the end of the 9th, 11th, 13th, 14th and 18th weeks, the rats were sacrificed for plasma collection. The concentrations of plasma IgG and lysine were detected. Plasma IgG was purified, identified, hydrolyzed and derived. The enrichments of 2H-alanine in plasma and 2H-alanyl in IgG were determined. The fractional synthesis rates (FSR) of plasma IgG and synthesis kinetic equations were calculated. Results The FSRs of plasma IgG in rats were 8.82%/w, 17.87%/w and 24.77%/w in the low, normal and high lysine group respectively. The corresponding synthesis kinetic equations were: ft = 0.1116×(1-e^00882t), ft = 0.0781×(1-e^-0.1787t) andft = 0.0741 ×(1 -e^-0.2477t). The correlation coefficient between lysine intake and FSR was 0.99. Conclusion There was a positive correlation between lysine intake and plasma IgG FSR in rats.