Vyuziti HPLC ke stanoveni metotrexatu a folatu ve vzorcich telnich tekutin

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In vivo study of radioprotective effect of NO-synthase inhibitors and acetyl-L-carnitine

In vivo study of radiprotective effect of NO-synthase inhibitors and acetyl-L-carnitine This study investigated the protective effect of two nitric oxide synthase inhibitors N(omega)-Nitro-Larginine methyl ester (L-NAME, 100 mg/kg i.p.) and aminoguanidine (AG, 400 mg/kg i.p.), and an antioxidant acetyl-L-carnitine (ALC, 250 mg/kg i.p., once daily for five days) against radiation-induced damage in Wistar rats. Blood samples were collected 6 hrs after whole-body irradiation with 8 Gy. Plasma concentrations of nitrite+nitrate (NOx) and malondialdehyde (MDA) were measured by highperformance liquid chromatography. A single injection of L-NAME one hour before exposure effectively prevented the radiation-induced elevation of plasma NOx and it reduced 2.6-fold the risk for death during the subsequent 30-day period. Pretreatment with ALC prevented the radiation-induced increase in plasma MDA and it had similar effect on mortality as L-NAME did. Presumably due to its short half-life, the partially iNOS-selective inhibitor and antioxidant AG given in a single dose before exposure did not attenuate MDA and NOx and it failed to significantly improve the 30-day survival. In conclusion, pretreatment with both the nonspecific NOS inhibitor L-NAME and the antioxidant ALC markedly reduce mortality to radiation sickness in rats. The radioprotective effect may be directly related to effective attenuation of the radiation-induced elevation of NO production by L-NAME and of oxidative stress by ALC. Key words: acetyl-L-carnitine; aminoguanidine; ionizing radiation; N(omega)-Nitro-L-arginine methyl este