Ocular Inflammatory Responses in Diabetes

Abstract

Abstract: : Purpose: Diabetic patients are vulnerable to infection, which might result from the impairment of normal inflammatory reactions. This study was designed to evaluate the inflammatory reactions in the posterior segment of the eye, via observation of retinal leukocyte dynamics in inflamed diabetic rats. Method: Diabetes was induced in 6 weeks old male Long-Evans rats by intraperitoneal injection of streptozotocin (75mg/kg). Three weeks after diabetic induction, endotoxin induced-uveitis (EIU) was prepared by footpad injection of lipopolysaccharide (LPS). At 6, 12, 24, 48 hours after LPS injection, inflammatory leukocyte behavior was observed in vivo with acridine orange digital fluography, consisting of a scanning laser ophthalmoscope and a fluorescent nuclear dye of acridine orange. The aqueous humor was collected to evaluate cellular infiltration and protein concentration. Results: After injection of LPS, rolling and adhered leukocytes were found along the walls of the major retinal veins. The number of rolling leukocytes increased at 12 and 48 hours. The number of accumulated leukocytes reached a peak at 48hours. In the diabetic group, the number of rolling leukocytes decreased by 55% at 12hours, and the number of accumulated leukocytes reduced by 47% at 48hours. Moreover, leukocytes infiltration into the aqueous humor reduced in the diabetic group. Conclusion: This study suggests that, in the diabetic retina, interactions between leukocytes and endothelial cells are inhibited and result in suppression of LPS-induced inflammation. In diabetic conditions, the normal process of ocular inflammation may be impaired.

Keywords: diabetes • diabetic retinopathy • inflammation