Effects of ingestion of high protein or excess methionine diets by rats for two years.
Eighteen male Wistar rats weighing 230 g (9 wk old) were fed casein diets containing 10% protein (HC), 50% protein (HP) or 10% protein plus 2% DL-methionine (MET) for 2 yr. In HC rats, mean body weight was 570 g; the carcass contained 13.5% protein and 37% lipid. The HP-fed rats had a 100 g lower body weight than HC rats due solely to a smaller amount of body lipid. Liver urea concentration and kidney weight were higher in HP rats than in HC rats. The body weight of MET-fed rats was lower than the other two groups and body lipid was only 30% that of HC rats. Histologic examination showed a normal aspect of the thoracic aorta from HC rats, whereas in HP, moderate signs of vascular aging--thicker intima and media with hypertrophy of smooth muscular cells (smc) with collagen enrichment and diffuse fibrosis--were observed. Aortas from MET rats also exhibited thicker intima and media due to smc hypertrophy. Some smc presented degenerative aspects and necrosis; other smc were replaced by chondroid cells and foci of fibrosis, resulting in a loss of the distension capacity of the aorta. Such an advanced stage of vascular aging is not normally found in 2-yr-old rats.
Fau
D
D
Centre de Recherches sur la Nutrition, CNRS, Meudon-Bellevue, France.
Peret
J
J
Hadjiisky
P
P
D000375:Aging / Q000473:pathology*; D000818:Animals; D001158:Arteries / Q000473:pathology* / Q000503:physiopathology; D001835:Body Weight; D002364:Caseins; D004044:Dietary Proteins / Q000008:administration & dosage*; D005355:Fibrosis; D006984:Hypertrophy; D008297:Male; D008715:Methionine / Q000008:administration & dosage*; D009929:Organ Size; D051381:Rats; D011919:Rats, Inbred Strains
D002364:Caseins; D004044:Dietary Proteins; D008715:Methionine