thiobarbituric-acid and Cerebrovascular-Disorders

We examined the effect of high potassium (K) diet on oxidative stress to endothelium in hypertensive rats. Five-week-old stroke-prone spontaneously hypertensive rats (SHRsp) were fed a 5% high NaCl diet containing either 0.5% normal K (n = 28) or 2.1% high K (n = 19) for 6 weeks, and lipid peroxides in the aortic intima and plasma were measured. Lipid peroxides were extracted into an organic solvent to avoid the interference of carbohydrates or glycoproteins, and malondialdehyde (MDA) produced from lipid peroxides by acid-heating was measured by its reaction to thiobarbituric acid. The antioxidant butylated hydroxytoluene prevented spurious lipid peroxide formation during the whole procedure, and optimum Fe3+ allowed a maximum MDA production from lipid peroxides. The high K SHRsp showed lower lipid peroxide levels than the normal K SHRsp both in the intima (5.6 +/- 0.3 vs. 7.2 +/- 0.4 nmol MDA/mg fatty acids, p < 0.003) and plasma (0.91 +/- 0.08 vs. 1.46 +/- 0.10 nmol MDA/ml, p < 0.001). Mean arterial pressure was slightly lower by 13 mmHg in the high K SHRsp, but these differences were still obvious even when we compared groups of rats with precisely matching blood pressures. These results indicate that high K diets reduce oxidative stress on the endothelium of high NaCl-fed SHRsp independently of blood pressure changes. This effect may be involved in the mechanism by which high K diets protect endothelium and reduce stroke incidence in hypertensive animals. Thus, we improved the method of lipid peroxide measurement and propose the protective effects of high K diet against oxidative stress to endothelium in hypertension animals.

Topics: Animals; Antioxidants; Blood Vessels; Butylated Hydroxytoluene; Cerebrovascular Disorders; Endothelium, Vascular; Ferric Compounds; Genetic Predisposition to Disease; Hypertension; Lipid Peroxides; Male; Malondialdehyde; Oxidative Stress; Potassium, Dietary; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Thiobarbiturates; Tunica Intima

Thiobarbituric acid (TBA) reactive substances in serum and cerebrospinal fluid from patients with cerebral apoplexy were determined and their relationship to this disease was studied. TBA reactants in serum were elevated in patients with cerebral apoplexy, but there was no difference between patients with brain tumor or other neurological disease and healthy persons. TBA reactants in cerebrospinal fluid in patients with cerebral aneurysm, cerebral arterial and venous anomalies or intracerebral hematoma, and its levels in patients with cerebral infarction or brain tumor were also higher than in healthy persons. Serum alpha-tocopherol levels were elevated in patients with cerebral infarction, but were relatively low in patients with cerebral aneurysm, cerebral arterial and venous anomalies or intracerebral hematoma. The reverse was the case with cerebrospinal fluid levels of alpha-tocopherol. That is, the sequence of decreasing level of alpha-tocopherol in cerebrospinal fluid was intracerebral hematoma, cerebral aneurysm, cerebral arterial and venous anomalies, and cerebral infarction. The levels of TBA reactive substances in patients with cerebral apoplexy showed a positive correlation between serum and cerebrospinal fluid, and the levels of alpha-tocopherol showed a similar correlation.

Topics: Aged; Cerebrovascular Disorders; Female; Humans; Lipids; Male; Middle Aged; Thiobarbiturates; Vitamin E