Photically-induced retinal damage in diabetic rats

Abstract

The present study examines the interaction of light damage to the retina and streptozotocin (SZ)-induced diabetes in male and female rats during the early development of the disease, when changes occur in the blood-retinal barrier and in pigment cell membranes. Exposure of rats to low illuminance was used to determine the relationship between photically-induced cell death and diabetes. Other groups of animals were exposed to a greater illuminance for shorter time periods (24 hours) in attempts to identify a specific post-treatment day for the effect of diabetes. Blood glucose levels were monitored to indicate the severity of the diabetes. Morphometric analyses and histopathologic observations demonstrated that the outer nuclear layer (ONL, photoreceptor nuclei) was reduced significantly in thickness in female rats exposed to light during a 9 day period after SZ injection, but was unchanged from the control groups when exposed beginning at 12 days after SZ treatment. Removal of the pituitary gland prior to SZ treatment and light exposure resulted in the survival of more photoreceptor cells and prevented the differential in ONL thickness observed between control and diabetic intact animals. Attempts to establish a period of greatest susceptibility of the diabetic retina to photic damage were unsuccessful, but results indicate that prior light history and/or shipment stress might be related to retinal damage from light exposure.

Photic Retinopathy After Cataract Surgery in Diabetic Patients

“…30 Other research has shown similar changes in the retinal pigment epithelium after albino rats were exposed to a brief period of intense light 19 or to longer periods of continuous, low-intensity visible light. 17 In this study, we found very few patients (0.62%) who developed PR after cataract surgery. This frequency is low compared with rates in previous investigations, which may be the consequence of improved operative techniques with more frequent use of phacoemulsification in cataract surgery.…”

Services to Operate and Maintain the Microwave Research Facility at Brooks Air Force Base, San Antonio, Texas

“…Under anesthesia, a 2-hour exposure to 1 mW/cm 2 of 463-nm radiation produced extensive damage to the retinal pigmented epithelium. In comparison to rats maintained under 750 lux (0.11 mW/cm 2 ), 14:10 light-dark cycle, a significant reduction in thickness of the outer nuclear layer was noted in rats maintained under 1080 lux (0.16 mW/cm 2 ) constant light for 9 days or longer [Johnson et al 1986]. It has also been demonstrated that long term light history of animals determined the sensitivity of the photoreceptors to light damage [Birch andJacobs 1980, Noell andAlbrecht 1971].…”

Effect of sevoflurane preconditioning on light-induced retinal damage in diabetic rats

“…This is consistent with other studies that have shown electrophysiological changes of ERG and VEP after photostress in diabetes type 1 without retinopathy [ 43 ]. Also histological analyses have shown reduced outer nuclear layer after a period of 9 days of light exposure in streptozotocin injected animals when compared to control group [ 44 ]. Other studies have reported that retinal deterioration due to white light was so severe in diabetic group after 42 days of light exposure to 1500-2000 mW/ m² during a 12 to 12 hour light-dark cycle, that ERG could not be recorded.…”