小米谷糠多肽对肝损伤及癌前病变的抑制作用

Inhibitory Effect of Millet Bran Polypeptides on Liver Injury and Precancerous Lesions

目的:观察小米谷糠多肽的抗肿瘤和抑制化学性肝损伤作用。方法:分别用菠萝蛋白酶、木瓜蛋白酶、537酸性蛋白酶水解小米谷糠,得到3种多肽;先用噻唑蓝法检测3种谷糠多肽的体外抗肿瘤作用,然后用抗肿瘤效果最好的多肽喂食经氨基比林-NaNO2诱导的肝损伤小鼠,并作肝组织学观察。结果:当菠萝蛋白酶水解的谷糠多肽质量浓度为50 mg/mL时,S180和H22肿瘤细胞的抑制率可达到56.28%和53.73%,该多肽在10 g/(kg·d)剂量可显著降低小鼠肝脏丙二醛含量和血清谷草转氨酶、谷丙转氨酶活性(P<0.01),并提高肝脏谷胱甘肽过氧化物酶活性(P<0.01)。组织切片显示,模型组小鼠肝细胞损伤严重,谷糠多肽高剂量组动物的肝细胞形态基本正常。结论:菠萝蛋白酶水解的谷糠多肽具有抑制肝损伤及癌前期病变的作用。

Objective： This study was aimed to investigate the antitumor activity of millet bran polypeptides （MBPEs） and their inhibitory effect on chemically induced liver injury. Methods： Three kinds of polypeptides were obtained by enzymatic hydrolysis of millet bran with bromelain, papain and 537 acid protease, respectively. MTT assay was applied to detect the in vitro antitumor effect of MBPEs. The mice with hepatic injury chemically induced by aminopyrine and sodium nitrite were fed with the polypeptide with the strongest antitumor effect, and the liver was histologically observed. Results： The inhibitory rates of MBPE （50 mg/mL） prepared with bromelain on S180 and I-I22 tumor cells were 56.28% and 53.73%, respectively. In the high-dose MBPE group （10 g/（kg.d））, the serum levels of aspartate transaminase （AST） and alanine tmmaminase （ALT） and the liver content of malondialdehyde （MDA） were significantly d~＇eased （P 〈 0.01）. The activity oflivea＂ glulathione peroxidase （GSH-Px） was significantly increased （P 〈 0.01）. The histological examination of the liver tissue showed that liver cells were severely injured. However, the morphology of hepatocytes in the high-dose group was basically normal. Conclusion： The polypeptides from millet bran hydrolyzed by bromelain have significantly inhibitory effects on liver injury and precancerous lesions.