Abstract
Purpose :
We reported that OBP-801 (OBP), a histone deacetylase, inhibits the fibrosis of filtering blebs in a glaucoma filtration surgery model (Yamamoto Y, et al. Sci Rep. 2020). The purpose of this present study was to investigate the effect of OBP on filtering blebs after Glaukos® PRESERFLO™ MicroShunt (MicroShunt) implantation in rabbit eyes.
Methods :
Ten eyes of 10 Japanese white rabbits were divided into the following 3 groups: 1) OBP group (n=4 eyes), 2) control group (n=3 eyes), and 3) mitomycin C (MMC) group (n=3 eyes). Prior to surgery, the OBP group eyes received 1 OBP (80 µl) eye drop, the control group eyes received 1 balanced salt solution (BSS; 80 µl) eye drop, and the MMC group eyes received subconjunctival injection of 0.02% MMC (100 µl), then MicroShunt implantation was performed on those 10 eyes. Next, the OBP group received OBP eye drops and the control group received BSS eye drops twice daily until 7-days postoperative. In the MMC group, no eye drops were administered post surgery. Post surgery, bleb formation was assessed by slit-lamp examination and intraocular pressure (IOP; measured via rebound tonometry) was evaluated over a 35-day time course. At 35-days postoperative, the rabbits were euthanized and the filtration bleb tissues were evaluated via hematoxylin and eosin (HE) staining, picrosirius red staining, and immunohistochemical analyses.
Results :
At 35-days postoperative, the IOP in all 3 groups was lower than that at before surgery, with no significant difference observed between the 3 groups. In regard to the bleb appearance, the MMC group had significantly more avascular areas. In the filtration bleb tissues, HE staining revealed the highest amount of eosin-positive collagen fibers in the MMC group, followed by the control group and the OBP group, in that order, and picrosirius red staining detected collagen I as the main composition of the collagen fibers. Immunohistochemical analyses confirmed α-smooth muscle actin positive cells in the filtering bleb tissues of all 3 groups, and they were most abundant in the MMC group and suppressed in the OBP group, thus suggesting that fibrosis of the bleb tissue was enhanced in the MMC group and suppressed in the OBP group compared to the control group.
Conclusions :
OBP inhibits fibrosis and has the possibility of maintaining the filtering bleb after MicroShunt implantation.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.