Retino-choroidal changes in endotoxin-induced uveitis in the rat

Area of Science:

• Ophthalmology
• Immunology
• Microbiology

Background:

• Lipopolysaccharide (LPS) from Gram-negative bacteria is a potent immune stimulant.
• Bacterial components can trigger inflammatory responses in various organs, including the eye.

Purpose of the Study:

• To investigate the induction and characteristics of acute ocular inflammation following Salmonella typhimurium lipopolysaccharide injection in Lewis rats.
• To describe the clinical, biochemical, and histopathological changes in the eye.

Main Methods:

• Lewis rats were injected with 100 micrograms of Salmonella typhimurium lipopolysaccharide in the foot pads.
• Ocular inflammation was assessed clinically, and aqueous humor protein concentration was measured.
• Histopathological examination of anterior and posterior eye segments was performed.

Main Results:

• Acute eye inflammation developed rapidly, starting within 0.5 hours and peaking at 18 hours post-injection.
• Increased aqueous protein concentration indicated breakdown of the blood-ocular barrier.
• Histopathology revealed inflammatory infiltrates and exudates in the anterior segment (anterior chamber, iris, ciliary body).
• Novel findings included posterior segment pathology: retinal vasculitis, hemorrhagic exudates, photoreceptor cell destruction, and choroidal infiltration.

Conclusions:

• Salmonella typhimurium lipopolysaccharide is a potent inducer of acute ocular inflammation in rats.
• The induced inflammation affects both anterior and posterior segments of the eye, with significant retinal and choroidal pathology.
• This model provides a valuable tool for studying LPS-induced ocular inflammatory diseases.