Differential expression of the lenticular antioxidant system in laboratory animals: a determinant of species predilection to oxidative stress-induced ocular toxicity?

Purpose: Various animal species have been used to study oxidative stress-induced cataractogenesis; however, given that differences in the expression of the lens antioxidant system may influence species susceptibility to oxidative stress, we compared and contrasted a broad spectrum of components of the lens antioxidant system in dog, rat, marmoset, and rabbit.

Methods: Lenses collected from beagle dogs, Sprague-Dawley rats, marmosets, and New Zealand white rabbits were assayed for reduced glutathione (GSH), and activities of copper-zinc and manganese superoxide dismutase (CuZn-SOD; Mn-SOD), catalase (CAT), glutathione peroxidase (GPX), gamma-Glutamylcysteine synthetase (GCS), glutathione reductase (GR), glutathione-S-transferases (GST), and glucose-6-phosphate dehydrogenase (GPDH), and Trolox equivalent antioxidant capacity (TEAC).

Results: Expression of the lens antioxidant system varied considerably between species.

Validation of MRI measurement of cardiac output in the dog: the effects of dobutamine and minoxidil.

The use of magnetic resonance imaging (MRI) for the measurement of cardiac output parameters in anesthetized adult male beagle dogs has been validated against a widely accepted thermodilution method. Using a multislice cine gradient echo MRI method to acquire images of the entire heart, left ventricular lumen volumes were measured at systole and diastole in seven animals. Cardiac output correlated well (R 2 = 0.

Advantages of glutamate dehydrogenase as a blood biomarker of acute hepatic injury in rats.

In a recent study in rats, alanine aminotransferase (ALT), the preferred plasma biomarker of hepatocellular injury in rats, was ineffective at detecting marked hepatic necrosis produced by acetaminophen (Human and Experimental Toxicology 19, 277-83, 2000). In contrast, glutamate dehydrogenase (GLDH) was markedly elevated. Accordingly, these enzymes were comprehensively evaluated as plasma biomarkers of hepatocellular injury in rats using several other models of hepatic injury, including partial hepatectomy and exposure to methapyrilene, dexamethasone, cyproterone, isoniazid, lead nitrate, and Wyeth-14643.

Effect of diquat on the antioxidant system and cell growth in human neuroblastoma cells.

Oxidative stress elicits an adaptive antioxidant response, which varies with tissue type. Diquat, a potent redox cycler that generates reactive oxygen species, has been used to study oxidative stress; however, its effect on the antioxidant system has not been characterized in neuronal cells. Accordingly, we measured antioxidant parameters and cell growth in human neuroblastoma SH-SY5Y cells cultured for 48 h in medium containing 5, 10, or 25 microM diquat dibromide or phosphate-buffered saline.