Abstract
Abstract
OBJECTIVES
Osteoarthritis therapies are limited to symptom management and joint replacement. AMPA/kainate glutamate receptor (GluR) antagonists (NBQX/DNQX, 2.5–20mM) alleviate symptoms and disease in rodent models of osteoarthritis. We hypothesised that poly(lactic-co-glycolic) acid (PLGA) nanoparticles and thermoresponsive hydrogels sustain GluR antagonist release to improve their efficacy in an humanised 3D bone model of inflammation.
METHODS
Drug release in PBS (37 °C) was measured by HPLC of samples taken from 2.5mM NBQX/DNQX loaded PLGA nanoparticles (double emulsion) and thermosetting hydrogels (homogenised Pluronic-F127 (22%/25% w/v) and Carbopol 934 (0.5% w/v) with 2.5mM NBQX/DNQX in dH2O)(n=3). Y201 MSCs were cultured in 3D in rat tail collagen type I gels and exposed to IL-6/sIL-6r (5/40ng/ml), free NBQX (200μM) or NBQX loaded PLGA nanoparticles for 24 and 72hrs. Bone turnover, inflammatory and glutamate signalling markers were quantified by immunoassay and RTqPCR. Data analysed using t-test/ANOVA with Tukeys and principal component analysis (PCA)(SPSS).
RESULTS
Nanoparticles released 45% encapsulated DNQX over 3hrs followed by sustained release over 5 weeks. Thermoresponsive hydrogels released entire DNQX load over 27 hours (22 and 25% hydrogels). PCA revealed IL-6/sIL-6r treatment affected bone turnover, inflammation and glutamate signalling markers in vitro. Free NBQX treatment increased anti-inflammatory cytokine at 24hrs (IL-4, IL-10, IL-13) levels vs IL-6 treatment groups (p<0.05) and corrected IL-6 induced reduction in ALP expression (24hrs, p<0.05). Nanoparticle NBQX delivery induced increased IL-6 expression vs controls (72hrs, p<0.05) and increased glutamate and IL-6 protein release at (72hrs, p<0.05 and p<0.001 respectively).
CONCLUSIONS
Nanoparticles rapid release of DNQX (6.6μM /3 hours), mimics free drug effective in vivo but was followed by sustained release over 5 weeks. hydrogels released 2.5mM DNQX over a short time (27hrs). Free NBQX intervention mitigated bone turnover, inflammation and glutamate signalling changes following IL-6 exposure to bone cells in vitro.
Declaration of Interest
(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
