The Effect of Dietary Vitamin K1 Supplementation on Trabecular Meshwork and Retina in a Chronic Ocular Hypertensive Rat Model

Abstract

The pathophysiologic relationship between vitamin K and glaucoma remains largely unknown. The aim of the study was to explore the effect of dietary vitamin K supplementation in a rat glaucoma model. METHODS. Rats were randomly divided into two groups: standard diet and high vitamin K1 (VitK1) diet (300 mg VitK1/kg diet). Induction of chronic ocular hypertension by episcleral vein cauterization was performed on the right eye. The left eye with sham operation served as controls. Rats received standard or high VitK1 diets for 5 weeks after surgery until the end of experiment. Immunohistochemistry analyses of the retina and trabecular meshwork were performed. The change in coagulation function and IOP were evaluated. RESULTS. We observed a significant declined IOP at 2 weeks after surgery in the high VitK1 group compared with the control group. High VitK1 showed no significant effect on the body weight, rat phenotypes, or coagulation function. High VitK1 significantly inhibited the loss of retinal ganglion cells in the retina and increased the expression of matrix gla protein. High VitK1 also ameliorated the collapsed trabecular meshwork structure and increased collagen staining in the trabecular meshwork. CONCLUSIONS. High VitK1 intake inhibited the loss of retinal ganglion cells during glaucomatous injury, probably by increasing the expression of matrix gla protein. A transient decrease in the IOP was observed in the high VitK1 group, implying a potential effect of VitK1 on aqueous outflow. Retinal ganglion cells protection by high VitK1 supplementation may be due to the IOP-lowering effects as well as neuroprotective effect. Further research is required to delineate these processes.

Vitamin K and the Visual System: A Narrative Review

“…However, Wei et al 2018 [98] demonstrated circulating immature nonphosphorylated and uncarboxylated MGP (dp-ucMGP), a marker of reduced VK nutritional status, is a long-term predictor of reduced retinal arteriolar diameter, and referenced a number of studies linking retinal microvascular traits and generalized arteriolar narrowing with glaucoma [98]. A single in vivo study exploring the effect of dietary PK in a surgically induced ocular hypertension rat model was found [99]. Deng et al found that rats fed a high PK diet for a total of seven weeks were protected from retinal ganglion cell (RGC) loss and TM injury.…”

New strategies for neuro protection in glaucoma

“…In animal models of glaucoma, various diet-related treatments were found as non-IOP-related neuroprotective mechanisms. High VitK1 intake ( Deng et al, 2020 ) , Coenzyme Q10 + Vitamin E ( Zhang et al, 2017 ; Ekicier Acar et al, 2020 ), Nicotinamide riboside of the vitamin B3 family ( Zhang X. et al, 2021 ), probiotic bacteria ( Fafure et al, 2021 ) and other dietary supplementation ( Cammalleri et al, 2020 ) were proved to attenuate the loss of RGCs by regulating glia-mediated neuroinflammatory or BDNF activity, etc.…”