Vitamin E-induced chronic inflammation in rats

Area of Science:

• Pharmacology
• Immunology
• Toxicology

Background:

• Sub-plantar injection of vitamin E (VE) oil induces localized, chronic inflammation lasting over 8 weeks.
• The inflammatory response involves an initial neutrophil influx followed by sustained mononuclear cell pathology.

Purpose of the Study:

• To investigate the mediators involved in vitamin E-induced inflammation.
• To assess the role of different cell types in edema formation and white cell accumulation.
• To evaluate the efficacy of anti-inflammatory agents in suppressing VE-induced inflammation.

Main Methods:

• Utilized mediator inhibitors and depletors to identify inflammatory mediators.
• Conducted studies in leucopenic rats to differentiate edema and white cell accumulation.
• Tested the effects of corticosteroids and non-steroidal anti-inflammatory agents (NSAIDs) on VE-induced inflammation.

Main Results:

• Histamine, serotonin, kinins, and prostaglandins appear involved in the early inflammatory response.
• Edema formation and white cell accumulation may be dissociable, though cells are still mobilized in leucopenic rats.
• Corticosteroids effectively suppressed vitamin E-induced inflammation, while most NSAIDs showed limited efficacy.

Conclusions:

• Vitamin E oil triggers a complex inflammatory cascade involving multiple mediators.
• The inflammatory process exhibits distinct early and late phases with different cellular infiltrates.
• Corticosteroids are effective in managing vitamin E-induced inflammation, suggesting a role for glucocorticoid pathways.