Preclinical evaluations on the efficacy of a topical Chinese herbal formula for swelling control and pain relief

Abstract

Ethnopharmacological relevance: Patients suffering from musculoskeletal pain and swellings occupy many hospital beds and demand many rehabilitation facilities. Chinese Medicine is offering many alternatives to ameliorate pain and swelling. However, evidence-based scientific publications supporting their efficacy on pain relief are inadequate. The in vitro and in vivo efficacy of a topical use Chinese herbal bath formula (HB) on anti-inflammation and swelling control was studied. Materials and methods: The therapeutic mechanisms of HB were studied in vitro via anti-inflammatory and pro-angiogenic assays on RAW264.7 and HUVEC cells, respectively. Fibroblast proliferation was also studied with Hs27 cells. The in vivo angiogenic effect of HB was also studied using zebrafish model, while its efficacy of in vivo anti-Inflammation and swelling control were investigated using rat paw edema model. The affected paw was treated by immersing it in the HB or distilled water as control. The sensation of pain, change in paw thickness and inflammation marker in serum were analyzed. Results: In the anti-inflammation assay, HB significantly inhibited nitrite release from RAW264.7 by 47.6% at 800 μg/ml. In the pro-angiogenic assays, it reduced wound area in HUVEC by 8.2% and increased tube formation of HUVEC by 11.5% at 300 μg/ml. HB also stimulated Hs27 proliferation up to 23.5% at 1200 μg/ml. It showed in vivo pro-angiogenic effect by increasing the mean sprout number in the embryos of zebrafish by 2.4 folds. The in vivo therapeutic effects of HB on edema was illustrated by the significant longer thermal withdrawal latency and thinner paw thickness compared with control. After 14 days of treatment, HB also reduced the IL-6 concentration in the serum of rat by 20.9% significantly. Conclusions: This study showed that HB is effective for swelling control and pain relief from edema due to its anti-inflammatory and pro-angiogenic properties.