Study on the apoptosis mediated by apoptosis-inducing-factor and influencing factors of bovine muscle during postmortem aging

Area of Science:

• Biochemistry
• Cell Biology
• Postmortem Muscle Physiology

Background:

• Apoptosis is a crucial process in cellular regulation.
• Understanding apoptosis pathways is vital for various biological and food science applications.
• The role of apoptosis-inducing factors (AIF) in postmortem muscle changes requires further elucidation.

Purpose of the Study:

• To investigate the apoptosis pathway mediated by AIF in postmortem bovine muscle.
• To identify internal factors influencing AIF release and subsequent apoptosis.
• To characterize the mechanisms of AIF-mediated cell death in this context.

Main Methods:

• Quantification of AIF expression in mitochondria and nucleus.
• Assessment of caspase activity with and without caspase inhibitors.
• Measurement of optical density, mitochondrial swelling, reactive oxygen species (ROS) levels.
• Analysis of calpain I, cathepsin B, and cathepsin D activities, and Ca2+ concentration.

Main Results:

• AIF expression decreased in mitochondria and increased in the nucleus (P<0.05).
• Significant increases in nucleus optical density and mitochondrial swelling were observed (P<0.05).
• ROS levels showed a biphasic pattern; Ca2+ concentration, cathepsin B, and D activities increased, while calpain I activity decreased (P<0.05).

Conclusions:

• AIF-mediated caspase-dependent pathway represents a novel mitochondrial apoptosis pathway.
• Mitochondrial swelling, ROS content, Ca2+ concentration, and activities of calpain I, cathepsin B, and D are critical factors in postmortem bovine muscle apoptosis.