Corinne Regnault

Effect of encapsulation on the anti-inflammatory properties of superoxide dismutase after oral administration

Anti-inflammatory properties of free superoxide dismutase and superoxide dismutase encapsulated into liposomes, with or without ceramides, have been investigated. Two models were investigated: carrageenan paw oedema and pleurisy. Animals were fed by repeated doses, twice daily from day 1 until day 4. Evaluation consisted of measurement of paw oedema volume with determination of prostaglandin E2, thromboxane B2 and 6-keto-prostaglandin F1 alpha levels. Polymorphonuclear oxidative metabolism was evaluated by measurement of superoxide anion production. Levels of superoxide dismutase were determined in cells and pleural exudates. Higher anti-inflammatory effects were obtained after eight administrations of encapsulated forms (0.5 mg/kg) whereas free superoxide dismutase have shown no effects. Ceramides enhanced the results obtained.

Influence of Beta Carotene, Vitamin E, and Vitamin C on Endogenous Antioxidant Defenses in Erythrocytes

OBJECTIVE: To evaluate the in vivo radical scavenger activity of vitamin E, vitamin C, and beta carotene on erythrocyte membranes. DESIGN: A prospective, open trial without placebo. SETTING: Department of Clinical Pharmacy. PATIENTS: Ten healthy volunteers being supplemented with beta carotene, vitamin E, and vitamin C. MEASUREMENTS: Erythrocytes were incubated in water bath with 2,2′ azobis (2 amidinopropane) hydrochloride (AAPH). AAPH decomposes spontaneously at 37 °C to generate free radicals inducing membrane cellular damage and hemolysis. The absorbance was measured at 405 nm at 0, 30, and 60 min, and then every 20 minutes for four hours. The time for 50 percent of maximal hemolysis (T50%), which expresses the radical scavenger activity of erythrocytes, was determined. RESULTS: The physiologic T50% value determined in 52 healthy volunteers is 117 ± 12 min. Patients receiving these supplements have a higher value of T50% (143.2 ± 11.6 min at 30 d and 145.7 ± 10.5 min at 60 d) than the physiologic value (p<0.001). CONCLUSIONS: These data suggest that vitamin C, vitamin E, and beta carotene stimulate the radical scavenger activity of erythrocyte membranes after 30 days.

Kinetic evaluation of nitric oxide production in pleural exudate after induction of two inflammatory reactions in the rat

NO generation in the course of two acute, non immune, inflammatory reactions (pleurisy induced by rat isologous serum and carrageenan) was assessed by means of nitrite measurement in pleural exudate from 0.5 to 24 h. NO release varied time-dependently, similarly for the two inflammatory reactions. A first, but transient, peak was reached in 30 min while a second peak, more sustained, began at the fourth hour and was maximum at the tenth. Kinetic evolution of NO release was consistent with activation, in a first step, of a constitutive NO synthase probably from endothelial origin (inhibited by 2-Methyl-2-Thiopseudourea sulfate but not by dexamethasone) and with activation, in a second wave, of inducible NOS from endothelial and exudative cells. NO release was potentiated by administration per os of L-Arginine and seems to be involved in the evolution of acute inflammatory reactions and oxygen metabolite production.