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Age-related changes and tissue distribution of parvalbumin in normal and dystrophic mice of strain 129 ReJ
D S Greaves1, M J Dufresne, H B Fackrell
1Department of Biological Sciences, University of Windsor, Ontario, Canada.
Abstract:
In murine muscular dystrophy, hindlimb muscle contains a functionally defective thiol protease inhibitor (TPI) which has been implicated in the onset and progression of the disease in mice. More recently, this protease inhibitor has been identified as parvalbumin, a calcium binding protein. In this study, a polyclonal antibody against mouse muscle parvalbumin was used to study the concentration and distribution of this protein in normal and dystrophic male mice at various ages. Immunodetection assays were used to screen extracts of hindlimb, forelimb, brain, heart, lung, liver, and kidney in 60-day-old normal and dystrophic male mice for parvalbumin content. Parvalbumin was detected in relatively high amounts in both hindlimb and forelimb muscle extracts, while much lower concentrations were detected in brains of normal and dystrophic animals. No parvalbumin was detected in the lung, liver, heart, or kidney extracts using the immunoassay. With aging, the parvalbumin concentration in hindlimb muscle of normal mice remained fairly constant for 90 days, whereupon the level increased at 120 days. In contrast, the parvalbumin concentration in hindlimb muscle of dystrophic mice decreased steadily with age to about 22%% of normal animals at 120 days. The parvalbumin content was also reduced in dystrophic brain.
Insights
Parvalbumin, a calcium-binding protein, is deficient in muscular dystrophy mouse models. This study quanties parvalbumin levels in normal and dystrophic mice, revealing age-related declines in dystrophic muscle.
Area of Science:
- Biochemistry
- Molecular Biology
- Neuroscience
Background:
- Muscular dystrophy in mice involves a defective thiol protease inhibitor (TPI) in hindlimb muscle.
- This TPI has been identified as parvalbumin, a calcium-binding protein crucial for muscle function.
- Understanding parvalbumin's role is key to elucidating muscular dystrophy pathogenesis.
Purpose of the Study:
- To investigate the concentration and distribution of parvalbumin in normal and dystrophic mice.
- To analyze age-dependent changes in parvalbumin levels in various tissues.
- To establish parvalbumin as a potential biomarker for muscular dystrophy progression.
Main Methods:
- Utilized a polyclonal antibody against mouse muscle parvalbumin for immunodetection.
- Screened tissue extracts (hindlimb, forelimb, brain, heart, lung, liver, kidney) from normal and dystrophic mice.
- Quantified parvalbumin content using immunodetection assays at different ages.
Main Results:
- Parvalbumin was abundant in hindlimb and forelimb muscles of normal and dystrophic mice.
- Significantly lower parvalbumin concentrations were found in the brains of both groups.
- No parvalbumin was detected in heart, lung, liver, or kidney tissues.
- In normal mice, hindlimb muscle parvalbumin remained stable until 120 days, then increased.
- Dystrophic mice showed a steady decrease in hindlimb muscle parvalbumin with age, reaching 22% of normal levels by 120 days.
- Dystrophic brains also exhibited reduced parvalbumin content.
Conclusions:
- Parvalbumin levels are significantly altered in muscular dystrophy, particularly decreasing with age in dystrophic muscle.
- The findings suggest parvalbumin's altered expression is linked to muscular dystrophy.
- Parvalbumin may serve as a valuable indicator for disease progression and severity in mouse models.