Effect of Hydrogels and LipoxinA4 on Rat Periodontal Fibroblasts in-vitro

Poly-ethylene-glycol (PEG) based hydrogels have been recognized as a suitable vehicle for the delivery of bioactive molecules. Bioactives such as LipoxinA4 (LXA4) promotes resolution of inflammation and minimize localised alveolar bone loss in experimentally induced periodontitis. Objective: To evaluate the local effects of three types of biodegradable PEG based porous gels (polylactic acid-PEG triblock copolymer; hyperbranched polyester (Boltorn®)-PEG based copolymer; polyhedral oligomeric silsesquioxane [POSS]-PEG based copolymer) and LXA4 on the proliferation, viability and cell attachment of rat periodontal fibroblasts. Methods: Biodegradability of PEG based hydrogels were tested in 0.01M phosphate buffer saline(PBS), at 37±0.5°C in incubator prior in-vitro studies. Established primary rat periodontal fibroblast cells (1x10⁵) were used to evaluate the effects of PEG based porous gels and LXA4 on the proliferation (Countess, Invitrogen), viability (LIVE/DEAD® kit, Invitrogen;) and cell attachment (confocal microscopy), from days 1 to 5. Statistical analysis was done using ANOVA, Bonferroni multiple comparison tests. Results: All PEG based hydrogels degraded by 28 days. At days 1 and 3, proliferation of POSS and PEG triblock treated fibroblasts was significantly lower (p<0.001) compared to control group. At day 5, the viability of POSS treated fibroblasts was significantly reduced compared to day 3 POSS and day 5 Boltorn® treated groups. In LXA4 treated groups, at day 3, proliferation and viability of fibroblasts of 1µg LXA4 and 2µg LXA4 treated groups was significantly lower (p<0.001) than 500ng LXA4 and sham(PBS) treated groups. However at day 5, fibroblasts cell numbers in 1µg LXA4 and 500ng LXA4 treated groups were significantly higher (p<0.01) compared to 2µg LXA4 and sham treated groups. Confluence and cell attachment of fibroblast cells were observed on the surface of all types of PEG based hydrogels. Conclusion: low dose of LXA4, PEG triblock and Boltorn®20 copolymers induced proliferation and attachment of fibroblasts over time. Acknowledgments ADRF and IBRA.