Abstract
Purpose :
Most cases of uveitis are diagnosed at a young age and can have a negative impact on a person's socioeconomic status. Research has shown that 670 nm red light reduces inflammation in aging rodent eyes and in diabetic retinal lesions in mice. We tested the protective effect of 670 nm red light treatment in the rat model of endotoxin-induced uveitis (EIU).
Methods :
The EIU was conducted by injection of 0.5 ng lipopolysaccharides (LPS) into the posterior vitreous cavity of rats. These rats were randomly divided into the normal group, the sham-operated group, the EIU group, the EIU with 1,500 lux red light group, and the EIU with 3,000 lux red light group. After different procedures, the experimental groups were exposed to 670 nm red light for 1 hour. Then, the electroretinography (ERG) was arranged to check the change in the visual function. After sacrifice, the electron microscope was used to observe the morphological change of hyalocytes, retinal ganglion cells (RGCs), pericytes of retinal vessels, microglia cells, and even mitochondria of nerve fiber layers. The reverse transcription-polymerase chain reaction (RT-PCR) was used to check the levels of the mRNA expression of inflammation-related cytokines, apoptosis-related factors, mitochondrial proteins, and inflammasomes.
Results :
Based on the results of the ERG, 670 nm red light treatment reduced the injuries caused by the EIU. The 670 nm red light reduced the infiltration of hyalocytes and RGC death, decreased the activation of microglia and the vacuole formation in the pericytes of the retinal vessels, and maintained the structure of the inner membrane of mitochondria. The 670 nm red light therapy not only decreased the inflammation-related cytokines, such as NF-κB, TNF-α, and IL-6, but also inhibited the apoptosis via P53 and Bax. It also activated the mitochondrial functions through modulation of PGAM5 and Drp1. Besides, it inhibited the formation of NLRP3/ASC/Caspase-1 inflammasome complexes and thus downregulated the expression of IL-1β.
Conclusions :
Our findings suggested that 670 nm red light may provide a potential therapeutic effect in the rat EIU model.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.