初乳中酶活性及生物活性因子含量的动态变化及其意义

Dynamic changes of enzymes activities and growth factors contents in human colostrum

目的 探讨人初乳中超氧化物歧化酶 (SOD)、淀粉酶 (AM)和碱性磷酸酶 (ALP)活性及表皮生长因子 (EGF)和胰岛素样生长因子 1(IGF 1)含量的变化规律及其临床意义。方法 分别采用改良邻苯三酚自氧化法、碘 淀粉比色法和磷酸苯二钠法 ,测定 2 0例产妇的 118份初乳 (泌乳第 1～ 7天 )中SOD、AM和ALP活性 ;采用放射免疫法测定EGF和IGF 1含量。结果 初乳中SOD活性在开始泌乳的前 1～ 4天由 (18 7± 2 2 )kU/L上升到 (2 2 5± 2 9)kU/L ,然后下降 ,第 7天为 (11 2± 2 1)kU/L ,前 4天活性显著高于第 7天 (P <0 0 5或P <0 0 1)。AM和ALP活性在开始泌乳的 1周内逐渐下降 ,分别由 (15 5± 12 )kU/L和 (10 5± 17)kU/L ,下降到 (17± 4 )kU/L和 (5 4± 9)kU/L ,前 4天的AM活性显著高于第 7天 (P <0 0 5或P <0 0 1) ,第 1天的ALP活性显著高于第 7天 (P <0 0 5 )。初乳中EGF和IGF 1含量在开始泌乳的前 4天快速下降 ,分别由 (10 5± 11) μg/L和(2 5 9± 2 7) μg/L下降到 (40± 5 )μg/L和 (5 6± 1 3) μg/L ,在泌乳的第 4～ 7天变化较小。泌乳前 3天 ,EGF含量显著高于第 7天 (P<0 0 5或P <0 0 1) ,第 1天的IGF 1含量显著高于第 7天 (P <0 0 1)。结论初乳中具有高活性的SOD、AM和ALP 。

Objective To study the dynamic changes of the activities of superoxide dismutase (SOD), amylase (AM) and alkaline phosphatase (ALP) and of the contents of epithelium growth factors (EGF) and insulin growth factors (IGF-1) in human colostrum (lactation 1-7 days postpartum). Methods A total of 118 samples of human colostrum were taken from 20 healthy women postpartum. The activities of SOD, AM and ALP in human colostrum were determined by methods of pyrogallol autoxidation, colorimetry of iodine-starch and pyrocatechol phosphate respectively. EGF and IGF-1 contents in human colostrum were measured by radioimmunoassay. Results The SOD activity of human colostrum increased slightly during lactation 1-4 days postpartum, from (18.7±2.2) kU/L to (22.5±2.9) kU/L, then it tended to decrease, being (11.2±2.1) kU/L on the 7th day. The SOD activities in lactation 1-5 days postpartum were significantly higher than that on day 7 ( P <0.05 or P <0.01). AM and ALP activities of human colostrum gradually decreased within a week postpartum. AM activity declined from (155±12) kU/L to (17±4) kU/L. ALP activity declined from (105±17) kU/L to (54±9) kU/L. AM activities in lactation 1-5 days postpartum were significantly higher than that on day 7 ( P <0.05 or P <0.01);and ALP activity on the first lactation day was significantly higher than that on day 7 ( P <0.05). EGF and IGF-1 concentrations in human colostrum quickly declined during lactation 1-4 days postpartum. EGF concentration decreased from (105±11) μg/L to (40±5) μg/L, and IGF-1 concentration decreased from (25.9±2.7) μg/L to (5.6±1.3) μg/L. Both concentrations altered slightly during lactation 4-7 days postpartum. EGF concentrations in lactation 1-3 days postpartum were remarkably higher than that on day 7 ( P <0.05 or P <0.01);IGF-1 concentration on the first lactation day was significantly higher than that on day 7 ( P <0.01). Conclusions Human colostrum contains SOD, AM and ALP with high activities, and is also rich in EGF and IGF-1. All of these are indispensable to normal growth and development of infants. Breast-feeding should be emphasized and encouraged for infants.