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Vascular changes in DOCA hypertension. Influence of a low protein diet
Abstract:
The goal of this study was to characterize the influence of low protein diet on vascular changes induced by deoxycorticosterone acetate (DOCA) hypertension. DOCA hypertensive and control normotensive rats were placed on a low protein (5%) diet for 4 weeks. This intervention blocked the further increase in systolic blood pressure of rats treated with DOCA; systolic blood pressures of control rats were not influenced by the low protein diet. The sensitivity of isolated mesenteric arteries to norepinephrine was increased in DOCA hypertensive rats compared to that in arteries from control rats; arterial strips from rats maintained on the low protein diet were less sensitive to the catecholamine than arteries from their respective control diet group. Vascular sensitivity to calcium was identical in both normotensive and DOCA hypertensive rats, and the low protein diet had no effect on this measure of calcium activation. Calcium-induced relaxation was depressed in arteries from DOCA hypertensive rats, suggesting a decreased stabilizing influence of the cation on the excitable membrane. Arteries from rats maintained on the low protein diet showed enhanced relaxation to calcium compared to those from their respective control diet group. Membrane stores of calcium available for activation by norepinephrine were increased in arteries from DOCA hypertensive rats; the low protein diet decreased the storage capacity of these membrane sites. The total protein content of the aorta was increased in DOCA hypertensive rats and depressed to control level in DOCA rats maintained on low protein diet. No change was observed in actomyosin content nor in the actin-to-myosin ratio during the DOCA hypertension or the addition of a low protein diet. Since one action of DOCA is to increase cellular protein synthesis, the attenuation of these vascular changes in DOCA rats maintained on a protein-deficient diet is probably due to a decrease in available substrate.
Insights
A low protein diet partially reversed vascular changes associated with deoxycorticosterone acetate (DOCA) hypertension in rats. This dietary intervention reduced blood pressure and altered arterial sensitivity to norepinephrine and calcium.
Area of Science:
- Cardiovascular Physiology
- Nutritional Science
- Hypertension Research
Background:
- Deoxycorticosterone acetate (DOCA) hypertension is a model used to study cardiovascular changes.
- Dietary protein intake can influence blood pressure regulation and vascular function.
- Understanding the interplay between diet and hypertension is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the effects of a low protein diet on vascular alterations in DOCA-induced hypertension.
- To assess how dietary protein restriction impacts blood pressure, arterial sensitivity, and calcium handling in hypertensive rats.
Main Methods:
- Rats were subjected to DOCA hypertension or served as controls.
- Animals were fed either a control or a low protein (5%) diet for 4 weeks.
- Systolic blood pressure, mesenteric artery sensitivity to norepinephrine and calcium, and aortic protein content were measured.
Main Results:
- The low protein diet attenuated the rise in systolic blood pressure in DOCA hypertensive rats.
- Vascular sensitivity to norepinephrine was reduced, and calcium-induced relaxation was enhanced in rats on the low protein diet.
- DOCA hypertension increased aortic protein content, which was normalized by the low protein diet.
Conclusions:
- Dietary protein restriction can mitigate some vascular pathologies associated with DOCA-induced hypertension.
- Reduced substrate availability due to low protein intake likely underlies the attenuation of vascular changes.
- This suggests a role for dietary protein in managing hypertension-related vascular dysfunction.