Glucocorticoid localization by radioautography in the rabbit eye following systemic administration of 3H-dexamethasone

Effects of oral administration of anti-inflammatory medications on inhibition of paracentesis-induced blood-aqueous barrier breakdown in clinically normal cats

OBJECTIVE

To assess inhibitory effects of orally administered anti-inflammatory medications on paracentesis-induced intraocular inflammation in clinically normal cats.

ANIMALS

30 clinically normal domestic shorthair cats.

PROCEDURES

Cats were randomly assigned to a control group and 4 treatment groups. Cats in the treatment groups received an anti-inflammatory medication orally once daily at 7 AM (acetylsalicylic acid [40.5 mg/cat], meloxicam [0.1 mg/kg], prednisone [5 mg/cat], or prednisolone [5 mg/cat]) for 5 days beginning 2 days before paracentesis-induced breakdown of the blood-aqueous barrier (BAB) and continuing until 2 days after paracentesis. Paracentesis of the anterior chamber was performed in 1 randomly selected eye of each cat. Fluorophotometry was performed in both eyes of each cat immediately before (time 0) and 6, 24, and 48 hours after paracentesis.

RESULTS

At 24 and 48 hours after paracentesis, fluorescein concentration in the eye subjected to paracentesis in the cats receiving prednisolone was decreased, compared with that in the control cats. At 48 hours, a decrease in the fluorescein concentration was also apparent in the eye subjected to paracentesis in the cats receiving meloxicam, compared with that in the control cats. There was no evidence of treatment effects for acetylsalicylic acid or prednisone. There was no evidence of treatment effects in eyes not subjected to paracentesis.

CONCLUSIONS AND CLINICAL RELEVANCE

Orally administered prednisolone and meloxicam significantly decreased intraocular inflammation in clinically normal cats with paracentesis-induced BAB breakdown. Oral administration of prednisolone or meloxicam may be an effective treatment for cats with uveitis.

Cellular distribution of dexamethasone in rabbit spleen and lymph nodes

The binding of tritiated dexamethasone by rabbit spleen and lymph nodes was studied in vivo by dry radioautography. The labeled glucocorticoid was found in the surface and cytoplasm of eosinophil leukocytes and in the nuclei of reticular cells, plasmocytes, endothelial cells and macrophages, but not in lymphocytes, lymphoblasts or plasmoblasts. Additional administration of excess of excess of non-radioactive dexamethasone suppressed this labeling. The findings are discussed in relation to the mechanism of action of glucocorticoids in lymphoid organs.