ABSTRACT
The aim of this study was to investigate the utility of the Golgi-Cox method to characterize the distribution and morphological changes of the hepatic stellate cells (HSCs) in CCl4 liver damaged rats. Six-week-old male Wistar rats were injected with CCl4 for ten weeks. The livers were processed with the Golgi-Cox method, reticuline, and Massons Trichrome stains, and analyzed under light microscopy. Histological evaluation of livers was made through the METAVIR score. In normal livers, the HSCs show stellate form with abundant thin cytoplasmic processes, distributed into hepatic lobule, mainly in zone 1. In addition, an intricate and broad network of fibers with radial distribution from the central vein to the periphery of the hepatic lobule was observed. In CCl4 damaged livers, with METAVIR score I and II, HSCs showed a moderate increase in the soma size, in the cytoplasmic processes and in density, distributed in zone 2 and 3; changes associated with a decrease in network fibers. In livers with METAVIR score III and IV, the morphology changes of the HSCs consisted of a significant increase in the soma size, cut and fraying appearance of the emerging cytoplasmic processes, and a decrease in HSCs density, distributed mainly in zone 3, with a significant depletion of network fibers. Results show that Golgi-Cox stain is able to impregnate the HSCs and could be an additional tool to study the morphological changes of the HSCs in the different experimental pathological conditions of the liver.
ABSTRACT
Myocardial Ca(2+) overload and oxidative stress are well documented effects associated to isoproterenol (ISO)-induced myocardial necrosis, but information correlating these two issues is scarce. Using an ISO-induced myocardial infarction model, 3 stages of myocardial damage were defined: pre-infarction (0-12 h), infarction (12-24 h) and post-infarction (24-96 h). Alterations in Ca(2+) homeostasis and oxidative stress were studied in mitochondria, sarcoplasmic reticulum and plasmalemma by measuring the Ca(2+) content, the activity of Ca(2+) handling proteins, and by quantifying TBARs, nitric oxide (NO) and oxidative protein damage (changes in carbonyl and thiol groups). Free radicals generated system, antioxidant enzymes and oxidative stress (GSH/GSSG ratio) were also monitored at different times of ISO-induced cardiotoxicity. The Ca(2+) overload induced by ISO was counterbalanced by a diminution in the ryanodine receptor activity and the Na(+)-Ca(+2) exchanger as well as by the increase in both calcium ATPases activities (vanadate- and thapsigargine-sensitive) and mitochondrial Ca(2+) uptake during pre-infarction and infarction stages. Pro-oxidative reactions and antioxidant defences during the 3 stages of cardiotoxicity were observed, with maximal oxidative stress during the infarction. Significant correlations were found among pro-oxidative reactions with plasmalemma and sarcoplasmic reticulum Ca(2+) ATPases, and ryanodine receptor activities at the onset and development of ISO-induced infarction. These findings could be helpful in the design of antioxidant therapies in this pathology.
