酶抑制法测定m-AST试剂性能评价及其在肝病中的意义

Evaluation on the reagent performance for the determination of m-AST by enzyme inhibition method and the clinical significance of m-AST in patients with liver disease

目的评价酶抑制法测定天门冬氨酸氨基转移酶（AST）线粒体同工酶（m—AST）活性的性能，并探讨m—AST在肝脏疾病中的临床价值。方法采用酶抑制法检测m—AST活性[即采用蛋白酶完全抑制AST细胞质同工酶（c—AST）的活性，然后用速率法进行检测]，并与免疫抑制法比较。采用酶抑制法检测259例肝病患者（包括急性肝炎43例、慢性病毒性肝炎95例、肝衰竭20例、重型肝炎11例、肝硬化代偿期40例、肝硬化失代偿期9例、原发性肝癌41例）及220名健康体检者（正常对照组）m—AST活性，并与AST比较。结果酶抑制法批内变异系数（CV）为0．59％～2．23％，批间CV为5．24％～6．23％；回收率为101．6％～108．0％，平均为104．97％；线性方程Y=0．997X一1．51，r=0．9999，m—AST活性在450U／L内线性良好；可完全抑制1500U／L的c—AST活性；与免疫抑制法结果呈高度正相关（r=0．9998）；溶血对m—AST检测结果干扰较大；以95％可信区间（孟±1．96s）初步确定m—AST参考区间男性为3．1～9．5U／L，女性为2．5～8．7U／L。肝病患者m—AST活性均高于正常对照组（P〈0．05），并与AST呈正相关。正常对照组m—AST／AST比值为0．30±0．07，肝病患者m—AST／AST比值均低于正常对照组（P〈0．05），但变化不如m—AST活性明显。结论酶抑制法测定m．AST活性自动化程度高，结果准确可靠，重复性好，线性范围宽。m—AST活性能反映肝细胞损伤的严重程度，对肝脏疾病的临床分类和预后具有重要价值。

Objective To evaluate the performance of mitochondrial aspartate aminotransferase （m-AST） by enzyme inhibition method, and to investigate the clinical significance of m-AST in patients with liver disease. Methods The m-AST activity was determined by enzyme inhibition method, and the activity of cytosolic aspartate aminotransferase （c-AST） was inhibited by protease, and was determined by rate method. The results of enzyme inhibition method were compared with those of immune suppression method. A total of 259 patients with liver disease （43 patients with acute hepatitis, 95 patients with chronic viral hepatitis, 20 patients with liver failure, 11 patients with serious hepatitis, 40 patients with compensated liver cirrhosis, 9 patients with decompensated liver cirrhosis and 41 patients with primary liver carcinoma） and 220 healthy subjects （healthy control group） were enrolled. Serum m-AST activity was measured by enzyme inhibition method and evaluated. The m-AST activities were compared with aspartate aminotransferase （AST） activities. Results The within-run coefficient of variation （CV） of enzyme inhibition method was 0.59% -2.23%. The between-run CV was 5. 24%-6. 23%. The recovery rates were 101. 6%-108. 0% （ the average recovery rate was 104.97~/v ）. The linear equation was Y =0. 997X - l. 51, r = 0.999 9. The linearity was up to 450 U/L. The activity of 1500 U/L concentration of c-AST was inhibited completely. The data was positively correlated between enzyme inhibition method and immune suppression method （ r = 0.999 8 ）. Hemolysis had interference to the m-AST determination results. According to 95% confidence interval （x ＋ 1.96s）, the reference range of m-AST in males was 3.1-9.5 U/L, and that in females was 2.5-8.7 U/L. The activity of m-AST in liver disease group was higher than that in healthy control group （P 〈 0.05 ）, and was positively correlated with AST activity. The ratio of m-AST to AST in healthy control group was 0.30 ~ 0.07, and the ratio in liver disease group was lower than that in healthy control group （ P 〈 0.05）. The decrease degree of m-AST/AST ratio was lower than that of m-AST. Conclusions Enzyme inhibition method for m-AST activity had the advantages of high automation, reliability and wide linear range. The m-AST activity can reflect the degree of liver cell injury. It has significance on clinical classification and prognosis of liver disease.