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The effect of corticosteroids or nitrogen mustard on aqueous humor chemotactic activity induced by intravitreal
Abstract:
In rabbits intravitreal injection of endotoxin induces potent chemotactic activity for monocytes in aqueous humor. We have assessed the effect of methylprednisolone (30 mg/kg intramuscularly) or nitrogen mustard (1.75 mg/kg intravenously) on the generation of this chemotactic activity. Histologic changes, anterior chamber protein extravasation, and aqueous humor cellular infiltration were reduced by corticosteroids to a variable degree. However, even in animals with a marked reduction in protein extravasation or histologic change, chemotactic activity was substantially preserved. Similarly, nitrogen mustard induced a leukopenia without affecting the ability of endotoxin to generate chemotactic activity in aqueous humor. In contrast, corticosteroids reduced both protein extravasation and the generation of chemotactic activity induced by intravenously injected endotoxin. The results suggest that the chemotactic activity induced in the eye by intravitreal endotoxin may be locally synthesized and may be present without a substantial leukocytic infiltrate.
Insights
Endotoxin in rabbit eyes causes monocyte attraction. Corticosteroids and nitrogen mustard did not fully block this chemotactic activity, suggesting local synthesis in the eye.
Area of Science:
- Ophthalmology
- Immunology
- Pharmacology
Background:
- Intravitreal endotoxin in rabbits triggers significant monocyte chemotactic activity in the aqueous humor.
- Understanding the mechanisms behind this ocular inflammatory response is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the impact of methylprednisolone and nitrogen mustard on endotoxin-induced chemotactic activity in rabbit eyes.
- To determine if this activity is locally synthesized within the eye.
Main Methods:
- Rabbits received intravitreal endotoxin, followed by intramuscular methylprednisolone or intravenous nitrogen mustard.
- Assessed histologic changes, protein extravasation, cellular infiltration, and chemotactic activity in the aqueous humor.
Main Results:
- Corticosteroids partially reduced inflammation but largely preserved endotoxin-induced chemotactic activity.
- Nitrogen mustard caused leukopenia but did not inhibit endotoxin-induced chemotactic activity.
- Corticosteroids did reduce both inflammation and chemotactic activity when endotoxin was administered intravenously.
Conclusions:
- Endotoxin-induced chemotactic activity in the eye appears to be locally synthesized.
- The presence of chemotactic activity does not necessarily correlate with significant leukocytic infiltration.