Unraveling the parameters and biological mechanisms of CO2 laser therapy for acute pain relief.

Acute pain-related pathology is a significant challenge in clinical practice, and the limitations of traditional pain-relief drugs have made it necessary to explore alternative approaches. Photobiomodulation (PBM) therapy using CO2 laser has emerged as a promising option. In this study, we aimed to identify the optimal parameters of CO2 laser irradiation for acute pain relief through in vivo and in vitro experiments. First, we validated the laser intensity used in this study through bone marrow mesenchymal stem cells (BMSCs) experiments to ensure it will not adversely affect stem cell viability and morphology. Then we conducted a detailed evaluation of the duty cycle and frequency of CO2 laser by the hot plate and formalin test. Results showed a duty cycle of 3% and a frequency of 25 kHz produced the best outcomes. Additionally, we investigated the potential mechanisms underlying the effects of CO2 laser by immunohistochemical staining, and found evidence to suggest that the opioid receptor may be involved in its analgesic effect. In conclusion, this study provides insights into the optimal parameters and underlying mechanisms of CO2 laser therapy for effective pain relief, thereby paving the way for future clinical applications.

Resveratrol Protects Murine Chondrogenic ATDC5 Cells Against LPS-Induced Inflammatory Injury Through Up-Regulating MiR-146b.

BACKGROUND/AIMS: Resveratrol (RSV) has been reported as a promising oral supplementation for osteoarthritis treatment, while the mechanism of its action is still unclear. The specific aim of this study is to decode one of the mechanisms by which RSV protects chondrocyte. METHODS: Mouse chondrogenic cell line ATDC5 was treated with 30 µM RSV for 24 h, and 10 µg/ml LPS for 12 h, after which cell viability, apoptosis, and the release of pro-inflammatory cytokines were assessed. The expression of miR-146b in ATDC5 cells was silenced by the specific inhibitor transfection, and then cell viability, apoptosis and inflammation were re-assessed. RESULTS: The IC50 value of LPS in ATDC5 cells was about 10.27 µg/ml. LPS with a dosage of 10 µg/ml repressed cell viability, induced apoptosis, and increased the release of IL-1ß, IL-6 and TNF-α. RSV pre-treatment (30 µM) significantly alleviated LPS-induced apoptosis and inflammation. More importantly, miR-146b was up-regulated by RSV, and the protective functions of RSV on ATDC5 cells were attenuated by miR-146b silence. Further, NF-κB and p38MAPK pathways were activated by LPS, and were deactivated by RSV. Besides, RSV-induced the deactivation of NF-κB and p38MAPK pathways was reversed by miR-146b silence. CONCLUSIONS: Our findings suggest that RSV protects ATDC5 cells from LPS-induced inflammatory and apoptotic injury via up-regulation of miR-146b and thereby deactivation of NF-κB and p38MAPK pathways.