Abstract
Purpose :
Non-swelling, biodegradable poly(ethylene glycol)-based oligo-tetra-hydrogels have shown potential as a vitreous substitute with regard to their physical properties. However, for clinical application of this technology, the host response when the material is implanted must be well understood. This study was conducted to investigate in vitro macrophage reactions to oligo-tetra-hydrogels.
Methods :
A degradable oligo-tetra-hydrogel, in which the polymers contain hydrolysable bonds, and a non-degradable oligo-tetra-hydrogel were evaluated. Each type of oligo-tetra-hydrogel was incubated in phosphate-buffered saline (PBS) at 45°C for 0, 18, or 25 days. Then, mouse macrophage-like RAW264.7 cells were cultured indirectly with each prepared hydrogel, which was inserted into the culture medium on a porous membrane insert, for 48 h at 37°C. The cells were also cultured in the presence of PBS or lipopolysaccharide as a negative and positive control, respectively. Viability of the RAW264.7 cells was determined by a Cell Counting Kit-8 assay, and their TNF-α production level was quantified by enzyme-linked immunosorbent assay. Student’s t-test was used for statistical analysis of the results, and statistical significance was defined as P less than 0.05.
Results :
The degradable oligo-tetra-hydrogel became completely degraded in 25 days at 45°C. Thus, RAW264.7 cells were exposed to the degradation products released from the hydrogel. Neither the degradable nor the non-degradable oligo-tetra-hydrogels had any effect on viability of the RAW264.7 cells during the 48-h incubation; relative cell viability of the hydrogel groups did not differ significantly from the control (degradable, P = 0.12; n = 3; non-degradable, P = 0.20; n = 3; Student's t-test). In addition, the level of TNF-α production was not significantly increased by either degradable or non-degradable hydrogels (control = 0.9 ± 0.13 pg/μg protein; degradable = 1.2 ± 0.41 pg/μg protein, P = 0.32; n = 3; non-degradable = 1.1 ± 0.85 pg/μg protein, P = 0.15; n = 3; Student's t-test).
Conclusions :
These results show that macrophages were not activated by oligo-tetra-hydrogel degradation products, and they suggest that oligo-tetra-hydrogels are promising candidates for use as a biocompatible artificial vitreous body.
This is a 2021 ARVO Annual Meeting abstract.