Effects of hyperbaric oxygen treatment in post-ischemic muscle. A quantitative morphological study

Area of Science:

• Biomedical Engineering
• Muscle Physiology
• Oxygen Therapy

Background:

• Ischemia leads to significant muscle damage, characterized by edema and altered metabolism.
• Hyperbaric oxygen (HBO) therapy is known to reduce edema and improve aerobic metabolism in post-ischemic muscle.
• Understanding HBO's morphological effects on skeletal muscle is crucial for optimizing treatment strategies.

Purpose of the Study:

• To investigate the histological, histochemical, and ultrastructural effects of HBO on post-ischemic skeletal muscle morphology.
• To quantify the impact of HBO on muscle cell damage markers using morphometry.
• To determine the efficacy of HBO in mitigating ischemia-induced changes in skeletal muscle.

Main Methods:

• Utilized histological, histochemical, and ultrastructural analyses on rat hindlimb skeletal muscle biopsies.
• Interrupted hindlimb circulation for 3 hours, with biopsies collected at 5 and 12 hours post-ischemia.
• Employed morphometry to quantify changes in muscle enzyme activity (phosphorylase) and mitochondrial size.

Main Results:

• Ischemic skeletal muscle exhibited reduced phosphorylase activity, a marker of cell damage.
• HBO treatment (2.5 ATA for 45 min) significantly increased the cross-sectional area with positive phosphorylase activity at 5 hours post-ischemia.
• While HBO prevented mitochondrial swelling, it did not significantly reverse other ultrastructural ischemic changes; multiple treatments were required to sustain effects at 12 hours.

Conclusions:

• HBO treatment effectively prevents the reduction of phosphorylase activity in post-ischemic skeletal muscle.
• Phosphorylase activity serves as a sensitive indicator of muscle cell damage, largely preserved by HBO.
• HBO demonstrates therapeutic potential in preserving skeletal muscle morphology and function following ischemic events.