氧化酪蛋白对小鼠血液和消化器官氧化损伤的影响

EFFECT OF OXIDIZED CASEIN ON THE OXIDATIVE DAMAGE OF BLOOD AND DIGESTIVE ORGANS IN MICE

目的评估H2O2-Cu及脂质氧化产物丙二醛(MDA)氧化修饰的酪蛋白对小鼠血液和消化器官氧化损伤的影响。方法用H2O2-Cu、MDA处理酪蛋白,测定蛋白体外蛋白消化率及消化产物清除自由基的能力。用氧化酪蛋白饲喂小鼠10 w,测定小鼠血液和消化器官的抗氧化及氧化损伤指标。结果酪蛋白经过氧化处理后,羰基、双酪氨酸(Dtyr)、氧化蛋白晚期产物(AOPP)含量上升,巯基含量下降。氧化蛋白体外消化率下降,消化液清除自由基能力下降。饲喂氧化酪蛋白日粮组小鼠的血液和消化器官氧化还原状态失衡,谷胱甘肽过氧化物酶(GSH-Px),过氧化氢还原酶(CAT)活性及总体抗氧化(T-AOC)能力下降,并积累大量活性氧(ROS)和氧化蛋白产物,包括羰基、MDA、Dtyr、AOPP。小鼠体重增长率下降,脏体比上升。结论氧化导致酪蛋白消化率和蛋白消化液清除自由基能力下降,摄食氧化酪蛋白降低机体抗氧化能力,导致消化器官的氧化损伤和机体营养状况的恶化。

Objective To evaluate the impacts of the oxidized casein on oxidative damage of blood and digestive organs in mice. Method Casein was oxidized by H：O2 combined with Cu （II） （H202-Cu） and MDA, then casein digestibility in vitro and free radical scavenging ability of casein digestive products were measured. After 10 w feeding, oxidative damage indicators in blood and digestive organs, including liver, pancreas and jejunum were detected. Results The contents of advanced oxidation protein products （AOPPs）, dityrosine （Dtyr） and carbonyl in oxidized casein increased, while thiol content decreased. Protein digestibility in vitro and free radical scavenging capacity of gastric juice decreased. The digestive organs lost their redox balance. The contents of ROS, carbonyl, MDA, Dtyr and AOPP increased （P〈0.05）, and GSH-Px, CAT and total antioxidant capacity （T-AOC） significantly decreased （P〈0.05） in oxidized casein group. Growth rate decreased, while viscera index （liver, pancreas） increased. Conclusion Oxidized casein could cause oxidative stress and accumulation of protein oxidation products in digestive organs.