Second hit post burn increased proximal gut mucosa epithelial cells damage

Area of Science:

• Immunology
• Gastroenterology
• Trauma Research

Background:

• Secondary infections and gut mucosal disruption are significant complications following severe burns, increasing morbidity and mortality.
• Previous research indicated that burns disrupt proximal gut mucosal homeostasis via increased epithelial cell apoptosis.

Purpose of the Study:

• To investigate the additive effects of secondary endotoxemia on proximal gut mucosal disruption following a severe burn.
• To determine the impact of lipopolysaccharide (LPS) administration on gut integrity and cell apoptosis in burn-injured mice.

Main Methods:

• C57BL/6 mice underwent 30% total body surface area scald burns.
• Mice received intraperitoneal saline or LPS (1 mg/kg) 72 hours post-burn.
• Proximal small bowel was analyzed for mucosal height, epithelial cell number, apoptosis (TUNEL), and proliferation (PCNA).

Main Results:

• Burn injury alone caused significant proximal gut mucosa impairment (decreased weight, height, cell number; increased apoptosis) by 12 hours, which partially recovered by 72 hours.
• Secondary endotoxemia (LPS administration) exacerbated gut mucosal damage, further decreasing weight, cell number, and mucosal height.
• Endotoxemia significantly increased small intestinal epithelial apoptosis and mucosal atrophy, demonstrating a detrimental "second hit" effect.

Conclusions:

• Severe burn injury disrupts proximal gut mucosal homeostasis.
• Secondary endotoxemia significantly worsens gut mucosal impairment and epithelial cell apoptosis following a burn.
• Endotoxemia acts as a critical secondary insult, exacerbating the initial burn-induced gastrointestinal damage.