Estimating relative carbonyl levels in muscle microstructures by fluorescence imaging

Area of Science:

• Biochemistry
• Cell Biology
• Aging Research

Background:

• Protein carbonyls are key biomarkers of oxidative stress.
• Oxidative stress and protein carbonyl accumulation are implicated in skeletal muscle aging.
• The precise distribution of protein carbonyls within skeletal muscle microstructures is not well understood.

Purpose of the Study:

• To develop and validate an immunohistochemical method for quantifying protein carbonyls in distinct skeletal muscle microstructures.
• To investigate the age-related distribution of protein carbonyls in skeletal muscle.

Main Methods:

• An immunohistochemical technique was employed using dinitrophenylhydrazine derivatization and Alexa 488-labeled antibody.
• Skeletal muscle microstructures (intermyofibrillar mitochondria, subsarcolemmal mitochondria, cytoplasm, extracellular space) were identified via specific cellular and organelle labeling.
• Alexa 488 fluorescence intensity was used to estimate relative protein carbonyl abundance.

Main Results:

• Preliminary data indicate significant age-related increases in protein carbonyls.
• The extracellular space exhibited the most substantial increase in carbonyls with aging.
• Subsequent decreases were observed in subsarcolemmal mitochondria, intermyofibrillar mitochondria, and cytoplasm.

Conclusions:

• The developed immunohistochemical method allows for the quantitative assessment of protein carbonyls in specific muscle compartments.
• Aging skeletal muscle shows a distinct pattern of protein carbonyl accumulation, with the extracellular space being most affected.
• This technique is adaptable for studying carbonyls in various muscle types and other tissues.