Background: Expression of toll-like receptor (TLR) 2 and 4 was up-regulated in lesional areas of OA cartilage. Hyperbaric oxygen (HBO) reduces the TLR signalling pathway in multiple organ failures. However, little is known about the effects of HBO on the catabolic pathway mediated by TLRs in human osteoarthritic (OA) chondrocytes.
Materials and methods: OA chondrocytes were separated from the knees of OA patients by performing sequential enzymatic digestion. Control cells were maintained in 5% CO2 / 95% air throughout the experiment. The hyperoxic cells were exposed to 100% O2 for 25 min and then to 5% CO2/95% air for 5 min at 2.5 ATA in a hyperbaric chamber. The mRNA or protein levels of TLR2, TLR4, iNOs, aggrecan, type II collagen, MMPs, and ADAMTSs were analyzed after HBO treatment. Production of nitric oxide (NO) was analyzed by the Griess reaction. Phosphorylation of MAPKs (p38, ERK, and JNK) was evaluated by phospho-kinase array kit.
Results: The mRNA levels of TLR 2, TLR 4, ADAMTS 4, and ADAMTS 5 were down-regulated while that of aggrecan and type II collagen were up-regulated in OA chondrocytes after HBO treatment. HBO led to decreased phosphorylation of p38, ERK, and JNK. Production of MMP 3, 9, 13 and NO was significantly decreased after HBO treatment.
Conclusion: Hyperbaric oxygen therapy reduces the catabolic pathway mediated by TLRs in human osteoarthritic chondrocytes.
17 May 2014 - 20 May 2014