灌胃不同剂量钙对大肠肿瘤模型大鼠肿瘤及血氨基酸的影响的实验研究

目的:研究不同口服剂量钙对大肠肿瘤和血清中氨基酸代谢的影响。方法:50只雄性Wistar大鼠适应性喂养一周后随机分为5组每组10只,碳酸钙灌胃6个月。对照组(钙摄入量0.5 g/kg/d)、模型对照组(钙摄入量0.5 g/kg/d)、低剂量钙组(钙摄入量1.0 g/kg/d)、中剂量钙组(钙摄入量1.5 g/kg/d)和高剂量钙组(钙摄入量2.0 g/kg/d)。模型对照组及低中高钙剂量组在实验的第2周开始,颈部皮下连续注射二甲基肼20周进行大肠肿瘤造模。大鼠解剖后观察肿瘤数量和直径,亚甲蓝染色观察大肠内异常隐窝(ACF)数量,HE染色观察腺癌发生情况。液相色谱-质谱联用检测大鼠血液中相关氨基酸含量。结果:从第20周开始,与模型组相比,中剂量钙组的体重增加,有显著性差异(P0.05)。在肿瘤数、肿瘤发生率、肿瘤平均直径和肠重这些指标中,中剂量钙组和高剂量钙组均显著低于模型对照组(均P0.05)。病理组织学结果显示,正常对照组未见任何组织增生,模型对照组以腺瘤为主,出现小部分腺癌。而其余各组均以腺瘤为主,未出现腺癌。与模型对照组相比,中剂量钙组的谷氨酸、谷氨酰胺、鸟氨酸均显著升高。结论:钙灌胃对大鼠大肠肿瘤发生具有抑制作用,血清中谷氨酸、谷氨酰胺和鸟氨酸的代谢发生变化。

Effect of Intragastric Administration of Different Doses of Calcium on Tumors and Blood Amino Acids in Rats with Colorectal Tumor Model

ABSTRACT Objective: To study the effect of different oral doses of calcium on tumorigenesis and amino acid metabolism in serum of colorectal tumor rats. Methods: Fifty male Wistar rats were randomly divided into 5 groups of 10 rats after one week of adaptive feeding, and calcium carbonate was intragastrically administered for 6 months. Control group (calcium intake 0.5 g/kg/d), model control group (Calcium intake 0.5 g/kg/d), low-dose calcium group (calcium intake 1.0 g/kg/d), medium-dose calcium group (calcium intake 1.5 g/kg/d), and high-dose calcium group (Calcium intake 2.0 g/kg/d). Model control group and low-medium-high-calcium-dose group started at the second week of the experiment. The neck was injected subcutaneously with dimethyl hydrazine for 20 weeks to perform colorectal tumor modeling. The number and diameter of tumors were observed, malignant blue staining was used to observe the number of abnormal crypts in the large intestine (ACF), and HE staining was used to observe the occurrence of adenocarcinoma. Liquid chromatography-mass spectrometry was used to detect the content of related amino acids in the blood of rats. Results: From the 20th week, compared with the model group, the weight gain of the medium-dose calcium group was significantly different (P<0.05). Among the indexes of tumor number, tumor incidence, tumor average diameter, and intestinal weight, the medium-dose calcium group and high-dose calcium group were significantly lower than the model control group (all P<0.05). Histopathological results showed that there was no tissue proliferation in the normal control group, and the model control group was mainly adenoma with a small proportion Adenocarcinoma. While the other groups were mainly adenomas, no adenocarcinoma appeared. Compared with the model control group, the glutamic acid, glutamine, and ornithine in the medium-dose calcium group were significantly increased. Conclusion: Calcium can inhibited the development of colorectal cancer and change the serum glutamine and ornithine in colorectal tumor rats.