Dose response of sulphur mustard: behavioral and toxic signs in rats.

The present study elucidates the behavioral and toxic signs in rats following dermal application of sulphur mustard (SM). Graded doses of SM (0.10, 0.25, 0.50, 0.75 and 1.0 LD50) were topically applied to male Wister rats. The body weight as well as behavioral/toxic signs and symptoms were recorded at 1, 2, 3, and 4th day after application of SM. Sulphur mustard consistently decreased body weights of rats in a dose and time dependent manner with maximum decrease on 3rd day post treatment. Sedation and diarrhea were significant in response to doses of SM intoxication in rats. It is concluded that the body weight, sedation and diarrhea may be used as a reliable parameter in evaluating SM intoxication. It is also suggested that hydration and hypertonic saline must be used as a rescue agent within 1-3 days after exposure to SM.

Comparative effects of exercise training on transcription of antioxidant enzyme and the activity in old rat heart.

An increase in antioxidant enzyme activity after acute exercise and exercise training have been reported by many investigators including our laboratory. This study was undertaken in order to determine whether an increase in activity of superoxide dismutase (MnSOD and CuZnSOD), catalase (CAT) and glutathione peroxidase (GSH-Px) during exercise training was associated with the increased levels of respective mRNAs. Male Fisher-344 rats (age 77 weeks) were given exercise training for 9 weeks on the treadmill. Enzyme activity and mRNA's were measured in the heart tissue 23 hr after stopping exercise training. The heart tissues of exercised and sedentary control rats were used to isolate mRNAs encoding MnSOD, CuZnSOD, CAT and GSH-Px by northern blotting experiments. The intensities of mRNA bands were measured by densitometric scanning of the autoradiograms. Northern blot for tubulin was used to normalize the respective intensities. Compared to sedentary controls, the level of mRNAs of enzymes MnSOD, CAT and GSH-Px were found to increase by 126 +/- 5, 133 +/- 6, and 138 +/- 5 percent of sedentary control (mean +/- SEM) respectively, due to exercise training. Corresponding values for these enzyme activity were 153 +/- 19%, 255 +/- 7%, 133 +/- 2% of sedentary control. These results suggest that post-translational modification of these enzyme activity increased in response to exercise training more than increased transcription in aged rats.

Exercise training generates ascorbate free radical in rat heart.

Exercise generates free radicals and can cause damage to the tissues. This investigation shows the formation of ascorbate radicals during exercise training (ET) which reduce the toxicity of free radicals. Male Fischer-344 rats (n = 8) (77 weeks old) were given exercise training (ET) on a treadmill with a low intensity of exercise that gradually increased from the first to the ninth week resulting in an average increase in respiratory exchange ratio, oxygen consumption rate and heat production. The sedentary control (SC) rats (n = 8) were not exercised and maintained under the same conditions. The heart tissues from different SC and ET rats were analyzed for ascorbate free radical (Asc.-) using electron paramagnetic resonance (EPR). The heart tissue from the ET and not from the SC rat showed the presence of Asc.-. This Asc.- was characterized by an EPR spectrum which showed doublet with a hyperfine coupling constant of 1.89 Gauss (0.189 mT). The benefit of exercise could be attributed to the formation of ascorbate radical in the heart muscle of the old rat. Exercise training can provide protection to the heart tissue against oxidative damage via ascorbate ion and vitamin E.