Effect of hydrogels or 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. One such bioactive, LipoxinA4 (LXA4) promotes resolution of inflammation and minimizes localised alveolar bone loss in experimentally induced periodontitis. Objective: To evaluate both biodegradable PEG based porous gels (polylactic acid-PEG triblock copolymer; hyperbranched polyester [Boltorn®]-PEG based copolymer; polyhedral oligomeric silsesquioxane [POSS]-PEG based copolymer) and the local effects of three types of gels or 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, at 37±0.5˚C in incubator. Established primary rat periodontal fibroblast cells (1x104) 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 1-5 days in culture. Statistical analysis was done using ANOVA, Bonferroni multiple comparison post tests. Results: All PEG based hydrogels degraded after 28 days. At days 1 and 3, proliferation of POSS treated fibroblasts was significantly lower (p<0.001) compared to the control. 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 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 significantly diminished on the surface of PEG triblock copolymer treated groups. Conclusion: Low doses of LXA4, PEG triblock or Boltorn®20 copolymers did not inhibit proliferation and attachment of fibroblasts over time. Acknowledgments ADRF and IBRA.