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Anti-endotoxin actions of methylprednisolone in the isolated perfused cat liver
Abstract:
The efficacy of the synthetic glucocorticoid, methylprednisolone, was examined in vitro using an isolated cat liver perfused with a blood-free medium. Addition of endotoxin (75 microgram/g tissue) to the perfusate did not change perfusion pressure or total oxygen consumption. However, cellular integrity was severely compromised as reflected by increases in perfusate lactate dehydrogenase and cathepsin D activities, increases in tissue lysosomal fragility, and enlargement and vacuolization of lysosomes. Addition of methylprednisolone (1 x 10(-3) M) to the perfusion medium prevented the endotoxin-induced changes in hepatocyte integrity. It is suggested that a major action of endotoxin in the liver is to increase lysosomal fragility, and the protective action of methylprednisolone appears to be related to its lysosomal stabilizing action. The potent anti-endotoxin action of glucocorticoids in vivo may be due in part to the stabilization of lysosomal membranes in tissues such as the liver.
Insights
Methylprednisolone protects cat liver cells from endotoxin damage by stabilizing lysosomes. This synthetic glucocorticoid prevents cell injury, suggesting a key mechanism for glucocorticoid therapy against endotoxin effects.
Area of Science:
- Hepatology
- Pharmacology
- Cell Biology
Background:
- Endotoxins can severely damage liver cells.
- Glucocorticoids are known to have protective effects against endotoxins.
- The specific mechanisms of glucocorticoid action in the liver require further elucidation.
Purpose of the Study:
- To investigate the in vitro efficacy of methylprednisolone against endotoxin-induced liver injury.
- To determine the effects of methylprednisolone on cellular integrity and lysosomal function in isolated perfused cat livers exposed to endotoxin.
Main Methods:
- Isolated cat liver perfusion with a blood-free medium.
- Administration of endotoxin and methylprednisolone to the perfusate.
- Measurement of perfusion pressure, oxygen consumption, lactate dehydrogenase, and cathepsin D activities.
- Assessment of tissue lysosomal fragility and lysosome morphology.
Main Results:
- Endotoxin significantly compromised hepatocyte integrity, increasing lysosomal fragility and enzyme leakage.
- Methylprednisolone (1 x 10(-3) M) effectively prevented endotoxin-induced damage to hepatocyte integrity.
- No significant changes in perfusion pressure or oxygen consumption were observed with endotoxin alone.
Conclusions:
- Endotoxin increases lysosomal fragility in liver cells.
- Methylprednisolone exhibits a lysosomal stabilizing action, protecting against endotoxin-induced liver injury.
- Lysosomal stabilization may be a key mechanism underlying the therapeutic effects of glucocorticoids in endotoxemia.