Resveratrol Ameliorates Retinal Ischemia/Reperfusion Injury Induced Cell Death in C57BL/6J Mice by Downregulation of Caspase-8 and Caspase-3.

Abstract

Purpose : Retinal cell death is a common pathology in eye diseases and one of the major causes of retinal damage, which can ultimately lead to blindness. I/R injury induces apoptosis in RGCs. Resveratrol (Res) is a potent natural antioxidant with beneficial effects in many ocular diseases, such as diabetic retinopathy, and glaucoma. Caspase-8 and caspase-3 expression are highly correlated with activation of the apoptotic pathway. Several regulators of caspase-8 have been identified, such as p53 and NF-κB. These proteins are not only associated with I/R injury, but also regulated by Res. It might be indirect evidence of increased transcription of caspase-8 in I/R injury. The present study aimed to determine whether Res regulates the expression of caspase-8 and caspase-3 in I/R retinal injury model.

Methods : C57BL/6J mice were injected with Res before I/R retinal injury induced by increasing the intraocular pressure for 1 h. After injury, Res was injected for more 2 days. Changes in retinal morphology were monitored after injury by histochemistry using hematoxylin and eosin staining. mRNAs and proteins were extracted in different time point after injury. The expression levels of caspase-8, p53 and NF-κB mRNA were determined using reverse transcriptase polymerase chain reaction (RT-PCR) and western blot analyses.

Results : I/R injury declines in retinal thickness and number of RGCs during 5 days after injury. p53, NF-κB, caspase-8 and caspase-3 mRNA expression increased and cleavage of caspase-8 and caspase-3 also increased by I/R injury. Res treatment reduced the significant loss of retinal morphology. Furthermore, Res treatment reduced the both of mRNA expression and caspase cleavage. This result suggests that I/R injury induced activation of caspase-8 and Res treatment ameliorates I/R injury.

Conclusions : In conclusion, up-regulated mRNA expression and cleavage of caspase-8 and caspase-3 indicates apoptosis activation. Res, however, suppresses apoptosis via downregulation of caspase-8 and caspase-3 activation. Our data suggest that Res is suitable as a therapeutic agent for treating I/R-related ophthalmic diseases by targeting the expression of caspase-8 and caspase-3.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.