Purpose: To compare the antifibrotic effect of vitamin E isoforms α-,γ-, and δ-tocotrienol on human Tenon’s fibroblasts (hTf) to the antimetabolite mitomycin C.
Methods: Antifbrotic effects of α- (40,60,80,100 and 120µM), γ- (10,20,330 and 40 µM) and δ–tocotrienol (10,20,30 and 40 µM) on hTf cultures were evaluated by performing proliferation, migration and collagen synthesis assays. Whereas for vitamin E the exposure time was set to 7 days to mimic subconjunctival application, cultures were exposed only 5 min to mitomycin C 100µg/ml to mimic intraoperative administration. Cell morphology (phase contrast microscopy) as an assessment for cytotoxicity and cell density by measuring DNA content in a fluorometric assay to determine proliferation inhibition was performed on day 0,4, and 7. Migration ability and collagen synthesis of fibroblasts were measured.
Results: All tested tocotrienol isoforms were able to significantly inhibit hTf proliferation in a dose dependent manner (maximal inhibitory effect without relevant morphological changes at day 4 for α-tocotrienol 80µm with 36.7% and at day 7 for α-tocotrienol 80µM with 42.6% compared to control). Degenerative cell changes were observed in cultures with concentrations above 80µM for α- and above 30µM for γ- and δ-rocotrienol. The highest collagen synthesis inhibition has been found with 80µM α-tocotrienol (62.4%) and no significant inhibition for mitomycin C (2.5%). Migration ability was significantly reduced in cultures exposed to 80µM α- and 30µM γ-tocotrienol (inhibition of 82.2% and 79.5%, respectively, compared to control) and also after mitomycin C treatment (60.0%). Complete growth inhibition without significant degenerative cell changes could only be achieved with mitomycin C.
Conclusion: In vitro, all tested tocotrienol isoforms were able to inhibit proliferation, migration and collagen synthesis of human Tenon’s fibroblasts and therefore may have the potential as an anti-scarring agent in filtrating glaucoma surgery.