Dietary vitamin e supplementation attenuates hypertension in Dahl salt-sensitive rats.
There is strong evidence that excess dietary salt (NaCl) is a major factor contributing to the development of hypertension. Salt-sensitive humans and rats develop hypertension even on a normal-salt diet. Salt sensitivity is associated with glucose intolerance and insulin resistance in both humans and animal models, including Dahl salt-sensitive (DSS) rats. In insulin resistance, impaired glucose metabolism leads to elevated endogenous aldehydes that bind sulfhydryl groups of membrane proteins, altering calcium channels, and increasing cytosolic free calcium ([Ca2+]i) and blood pressure. Vitamin E lowers tissue aldehyde conjugates, cytosolic [Ca2+]i, and blood pressure in spontaneously hypertensive rats and fructose-induced hypertensive Wistar Kyoto rats, models of insulin resistance. This study investigated the effect of a normal-salt diet on tissue aldehyde conjugates, cytosolic [Ca2+]i, and blood pressure in DSS rats and the effect of vitamin E supplementation on blood pressure and associated biochemical changes in these animals. Seven-week-old DSS rats were divided into 3 groups of 6 animals each and treated for 6 weeks with diets as follows: low-salt (0.4% NaCl); normal-salt (0.7% NaCl) and normal salt (0.7% NaCl) plus vitamin E (34 mg/kg feed). At completion, animals in the normal-salt group had significantly elevated systolic blood pressure, cytosolic [Ca2+]i, and tissue aldehyde conjugates compared with the low-salt group. They also showed smooth muscle cell hyperplasia in small arteries and arterioles of the kidney. Dietary vitamin E supplementation significantly attenuated the increase in systolic blood pressure and associated biochemical and histopathologic changes.
Vasdev
Sudesh
S
Department of Medicine and Laboratory Medicine, Health Sciences Centre, Memorial University of Newfoundland, St. John's, Newfoundland, Canada. svasdev@mun.ca
Gill
Vicki
V
Parai
Sushil
S
Gadag
Veeresh
V
D000447:Aldehydes / Q000378:metabolism; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D019587:Dietary Supplements; D004195:Disease Models, Animal; D004435:Eating / Q000187:drug effects; D006973:Hypertension / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D020303:Rats, Inbred Dahl; D014810:Vitamin E / Q000494:pharmacology* / Q000627:therapeutic use
D000447:Aldehydes; D000975:Antioxidants; D014810:Vitamin E; D002118:Calcium