beta-carotene and Proteinuria

Renal ischemia/reperfusion injury is a major cause of acute renal failure. The production of free radicals and reactive oxygen species are important factors contributing to ischemia/reperfusion injury. Thus, scavenging of the excess free radicals can be an important therapeutic approach. The present study examined the protective effect of beta carotene against renal ischemia/reperfusion injury in rat. Male adult Wistar rats (250-300 g) were exposed to 45 min of renal ischemia followed by 4 h of reperfusion. Beta carotene (10, 30 and 100 mg kg(-1)) or vehicle was administered for 5 days prior to ischemia. Renal function was assessed by plasma and urinary analysis. Present results showed that ischemia/reperfusion injury increased (p < 0.05-p < 0.001) serum urea and creatinine levels, as well as urinary excretion of protein and calcium and fractional excretion of sodium, while decreased glomerular filtration rate and potassium excretion. However, alterations in these biochemical indices due to ischemia/reperfusion injury were attenuated by beta carotene pretreatment (p < 0.05-p < 0.001), although not by all doses. Since, beta carotene administration improved renal function, it seems that beta carotene protects renal tissue against ischemia/reperfusion-induced oxidative damage.

Topics: Animals; beta Carotene; Blood Urea Nitrogen; Calcium; Creatinine; Female; Glomerular Filtration Rate; Humans; Kidney; Male; Potassium; Proteinuria; Random Allocation; Rats; Rats, Wistar; Reactive Oxygen Species; Reperfusion Injury; Sodium

The chemopreventive action of carotenoids on proteinuria and lymphadenopathy were examined in autoimmune-prone MRL-lpr/lpr (MRL/l) mice. They were fed a synthetic full-fed diet (16-18 kcal/mouse/day) with supplementation of beta-carotene or astaxanthin (0.19 mumoles/mouse, 3 times a week), and the development of lymphadenopathy and proteinuria were examined. MRL/l mice fed a full-fed diet without the supplementation of carotenoids or those fed a calorie-restricted (CR) diet (10-11 kcal/mouse/day, 60% calorie intake of full-fed mice) were employed as controls. CR dramatically delayed the development of proteinuria and lymphadenopathy, as reported previously. Carotenoids also significantly delayed the onset of these symptoms in MRL/l mice fed a full-fed diet. Carotenoids were half as effective as CR and astaxanthin, a carotenoid without provitamin A activity, which appeared to exert more significant preventive actions than beta-carotene in delaying the development of these symptoms. Similar chemopreventive actions of carotenoids were also demonstrated in MRL/l mice fed a regular diet (Lab Chow). CR has been shown to augment IL-2 production and to decrease serum prolactin levels in this strain, which may be related to its dramatic preventive action of autoimmunity. However, carotenoids did not affect IL-2 production nor prolactin levels in full-fed MRL/l mice. The chemopreventive actions of carotenoids observed in autoimmune-prone MRL/l mice may be attributed to yet unknown mechanisms, apart from their provitamin A activity or oxygen-quenching activity.

Topics: Animals; Autoimmune Diseases; beta Carotene; Body Weight; Carotenoids; Diet, Reducing; Energy Intake; Female; Food, Fortified; Interleukin-2; Lymph Nodes; Lymphocyte Activation; Lymphoproliferative Disorders; Mice; Mice, Mutant Strains; Organ Size; Prolactin; Proteinuria; T-Lymphocytes; Xanthophylls