Effects of halofuginone and pirfenidone on wound healing in experimental glaucoma filtering surgery

Various antifibrotic and antimetabolite agents are used for inhibiting wound healing during the perioperative period to improve the success of glaucoma filtration surgery. This experimental study was performed to investigate the effects of pirfenidone and halofuginone on wound healing in glaucoma surgery. In this study, 42 male New Zealand albino rabbits were randomly divided into six groups. Limbus based trabeculectomy was performed in five groups. Surgery was not performed and no drug was administered in the control group (Group I) . 0.9% NaCl and 1% corticosteroid were administered topically four times daily in for 14 days in group II and group III respectively after the surgery. İntraoperative 0.4 mg/ml mitomycin-C (MMC) was applied on to the scleral flap site for three minutes and in addition 1% topical corticosteroid was administered four times daily for 14 days in group IV after the surgery.0.5% topical pirfenidone+1% topical corticosteroid were administered four times daily in group V for 14 days after the surgery. İntraoperatively, sponge soaked halofuginone 10 ng/ml was applied on to the scleral flap site for three minutes and 1% topical corticosteroid was administered four times daily in group VI for 14 days after the surgery. Operated eyes of the rabbits were enuclated on the 15th day. Trabeculectomy tissues were excised. Histopathological sections were obtained from the bleb sites and Hematoxylin-Eosin and Masson-Trichrom staining were performed for evaluating fibroblast and mononuclear cells. Additionally, the intensity of TGF-β, FGF-β, and PDGF immunohistochemical stainings were evaluated. In terms of suppression of fibroblast and MNC, corticosteroid, MMC, halofuginone and pirfenidone groups were observed to be effective when compared with the sham group (p<0.05, p<0.05, p<0.05, p<0.05, respectively). No significant differences between pirfenidone and halofuginone group in terms of suppression of fibroblast and MNC were observed (p>0.05). However we found significant differences between these two and the other treatment groups (p<0.05, p<0.05, respectively).The immunohistochemical staining intensity of TGF-β and FGF-β were found to be suppressed significantly in all treatment groups vs the sham (p<0.05, p<0.05, p<0.05, p<0.05, respectively). In this aspect, significant differences were found between halofugione and pirferidone groups and the other treatment groups (p<0.05, p<0.05, respectively).PDGF staining intensity was significantly lower in all treatment groups (expect corticosteroid group) vs the sham (p<0.05, p<0.05, p<0.05, respectively). However, no difference was found between this treatment groups. As a result, pirfenidone and halofuginone were found to be effective on inhibiting wound healing and under the light of knowing the serious side effects of the currently used antimetabolites, these agents seems to be more efficient and safer in glaucoma filtration surgery. Keywords: Trabeculectomy, wound healing, MMC, pirfenidone, halofuginone