Basic research
The influence of diet supplementation with methionine on the pathomorphological changes of rabbit organs in experimental atherosclerosis

Introduction: The aim of this study was to examine the influence of methionine on the development of pathomorphological changes in the organs of rabbits in experimental atherosclerosis.

Material and methods: The experiment was carried out on three groups of 6 New Zealand rabbits that, for three months, were administered standard chow (C), cholesterol (CH), or cholesterol with methionine (CH + M) (doses: 0.5 g of cholesterol/rabbit/24 hours, 70 mg methionine/kg b.w./24 hours). Plasma lipids were monitored monthly. At autopsy, blood was collected for biochemical analyses and aorta, kidney, liver and heart were collected for histopathological tests. The pathomorphological changes in the organs were assessed with slides made by the normal paraffin method, stained with haematoxylin and eosin and by the freezing microtome method stained with Sudan III for detecting neutral fats. The activity of the most important antioxidative enzymes (SOD, total and both its isoenzymes, GPX) was indicated in the liver. The concentrations of 7-ketocholesterol and MDA were determined in the aorta.

Results: Presence of atheromatous plaque was noticed in the aorta, in the arterial vessels of the heart and of kidneys in both groups. The atherogenic changes in the CH + M group were of lesser intensity than in the CH group. In the CH + M group, steatosis of hepatocytes was of lesser intensity than in the CH group. There was focal steatosis in the tubule epithelium cells noticed only in kidneys of the CH group. Concentration of triglycerides and LDL cholesterol in the study groups was statistically increased when compared with the control group. Statistically an increase in the HDL cholesterol concentration was noted in the group CH + M after the 1st and 3rd month. There were no differences in the concentration of MDA in groups CH and CH + M in the aorta. A decrease in 7-ketocholesterol in the aorta in the CH + M group was noted in comparison to the CH group. The administration of methionine with cholesterol changed the activity of the studied enzymes.

Conclusions: It was found that methionine administered together with cholesterol atherogenic diet inhibited the atherogenic processes as well as fatty degeneration in livers and kidneys.