糖基化酪蛋白消化物对正常小鼠免疫调节作用的影响

Immunoregulatory Effect of Glycated Casein Digest in Normal Mice

美拉德糖基化反应能够诱导修饰蛋白质功能性质发生变化,但修饰后的蛋白质消化物对正常小鼠免疫状况的影响作用尚未评估。本研究利用酪蛋白与乳糖发生美拉德反应制备糖基化酪蛋白,用胰蛋白酶分别消化酪蛋白和糖基化酪蛋白得到酪蛋白消化物和糖基化酪蛋白消化物,以100、200 mg/kg mb和400 mg/kg mb的剂量分别灌胃两种酪蛋白消化物,连续28 d,测定小鼠脾脏指数、胸腺指数、血清生化指标、血清免疫球蛋白(immunoglobulin,Ig)M、IgA和IgG质量浓度、脾淋巴细胞增殖指数和自然杀伤(natural killer,NK)细胞活力。结果表明,与灌胃生理盐水的空白组小鼠相比,两种酪蛋白消化物处理组小鼠的免疫状况显著改善,血清生化指标提高,免疫器官指数、Ig质量浓度、脾淋巴细胞增殖指数及NK细胞活力等指标也显著提升(P<0.05);此外,酪蛋白消化物比糖基化酪蛋白消化物显示出更高的活性。因此,美拉德糖基化反应降低了酪蛋白消化物对正常小鼠免疫状况的提高作用。

The Maillard reaction, also known as glycation, causes changes to the functional properties of proteins, but the impact of digests of the modified proteins on the immune status of normal mice has not been evaluated yet. In this study, glycated casein was prepared via the Maillard reaction between casein and lactose, and glycated and native casein were separately digested with trypsin. Normal mice were administered with either digest at doses of 100, 200, and 400 mg/kg mb for 28 days. At 24 h after the last administration, the mice in each group were sacrificed for measurement of immune indices such as spleen and thymus indices, hematological parameters, serum immunoglobulin(Ig) M, IgA, and IgG concentrations, lymphocyte proliferation, and natural killer(NK) cell activity. The results showed that the mice administered with the two digests had increased values of all evaluated indices compared with those mice administered with physiological saline(P < 0.05), indicating that the digests were able to improve the immune statue of the mice. Furthermore, the immunoenhancing efficacy of native casein digest was higher than that of glycated casein digest. It is thus concluded that the Maillard reaction can weaken the enhancing effect of casein digest on the immune status of mice.