Acclimation to decompression: stress and cytokine gene expression in rat lungs

Area of Science:

• Physiology
• Molecular Biology
• Marine Biology

Background:

• Repeated compression-decompression (CDC) stress can lead to acclimation, reducing susceptibility to rapid decompression.
• Understanding the molecular mechanisms underlying this acclimation is crucial for preventing decompression sickness (DCS).

Purpose of the Study:

• To characterize inflammatory and stress-related gene expression in rats acclimated to rapid decompression.
• To investigate signal transduction pathways associated with decompression acclimation.

Main Methods:

• Rats were divided into control and acclimation groups, undergoing sham or actual dives.
• Lung tissue was analyzed for the expression of 13 inflammatory/stress genes and Akt/MAPK phosphorylation.
• Decompression sickness (DCS) incidence and severity were observed post-dive.

Main Results:

• Early growth response gene 1 (Egr-1) and TNF-α were upregulated in rats with DCS, with higher Egr-1 in non-acclimated rats.
• Acclimated rats showed reduced upregulation of IL-1β, IL-6, and IL-10 compared to control rats with DCS.
• Phosphorylated ERK1/2 was observed only in animals with DCS, while Akt phosphorylation was widespread.

Conclusions:

• Activation of ERK1/2, Egr-1, and associated cytokine genes may drive DCS initiation and progression.
• Downregulated expression of these genes in acclimated animals suggests a protective mechanism against DCS.
• This study provides initial insights into the molecular basis of decompression acclimation.