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Pyruvate attenuates myoglobin in vitro toxicity
Monica A Valentovic1, Jennifer Minigh
1Department of Pharmacology, Marshall University School of Medicine, 1542 Spring Valley Drive, Huntington, West Virginia 25704-9388, USA. alentov@marshall.edu
Abstract:
Myoglobinuria is a complication of crush injury as well as substance abuse. This study examined whether pyruvate modified myoglobin in vitro renal toxicity. Renal slices from Fischer-344 rats were incubated for 120 min with 0-12 mg/ml myoglobin. In an initial study, gluconeogenesis was stimulated by the addition of 10 mM pyruvate during the final 30 min. In all other studies, renal slices were incubated with myoglobin in the presence of 0 or 10 mM pyruvate for 120 min. Myoglobin increased lactate dehydrogenase (LDH) release and this was not modified by the presence of pyruvate for the last 30 min of the incubation. Myoglobin toxicity was reduced by coincubation of myoglobin with pyruvate for 120 min. LDH leakage was increased 1.2-, 1.7-, and 1.8-fold above control by 4, 10, and 12 mg/ml myoglobin, compared to 1.2, 1.3, and 1.3 fold in slices coincubated with 10 mM pyruvate, respectively. Myoglobin diminished adenosine triphosphate (ATP) levels but pyruvate maintained a 5x higher level of ATP within the slices. Glucose (10 mM) provided protection only for the low concentration (4 mg/ml) of myoglobin. Myoglobin induced oxidative stress while pyruvate prevented the rise in lipid peroxidation and glutathione disulfides by myoglobin. Myoglobin diminished total glutathione levels in pyruvate-treated tissue, but glutathione levels remained higher than tissues incubated in the absence of pyruvate. These results indicate that pyruvate reduced toxicity by preventing oxidative stress and via a supply of an energy substrate.
Insights
Pyruvate protects against myoglobin-induced kidney damage by reducing oxidative stress and providing energy. This study shows pyruvate significantly lowered markers of renal toxicity in vitro.
Area of Science:
- Biochemistry
- Nephrology
- Toxicology
Background:
- Myoglobinuria, a complication of crush injury and substance abuse, can lead to acute kidney injury.
- The direct renal toxicity of myoglobin and potential protective agents require further investigation.
Purpose of the Study:
- To investigate the in vitro effect of pyruvate on myoglobin-induced renal toxicity.
- To determine if pyruvate can mitigate cellular damage and energy depletion caused by myoglobin.
Main Methods:
- Renal slices from Fischer-344 rats were incubated with varying concentrations of myoglobin (0-12 mg/ml).
- Coincubation with pyruvate (10 mM) was performed for different durations (30 min or 120 min).
- Measurements included lactate dehydrogenase (LDH) release, adenosine triphosphate (ATP) levels, lipid peroxidation, and glutathione status.
Main Results:
- Myoglobin exposure increased LDH release and decreased ATP levels, indicating cellular damage and energy depletion.
- Coincubation with pyruvate for 120 minutes significantly reduced LDH leakage and maintained higher ATP levels compared to myoglobin alone.
- Pyruvate prevented myoglobin-induced oxidative stress, as evidenced by reduced lipid peroxidation and preserved glutathione levels.
Conclusions:
- Pyruvate effectively reduces in vitro renal toxicity induced by myoglobin.
- Pyruvate's protective mechanisms involve preventing oxidative stress and supplying an energy substrate.
- These findings suggest pyruvate as a potential therapeutic agent for myoglobinuric acute kidney injury.