Innovated formulation of TCM pangolin scales to develop a nova therapy of rheumatoid arthritis

Pangolin scale (PS) is a traditional Chinese medicine (TCM) for treating rheumatic arthritis (RA), and diverse medicinal formulations and therapeutic properties of PS have proved great potential to supplement conventional treatments in integrative medicine-based strategies. However, few studies have investigated how different PS formulations can impact the management of RA. Herein, we developed an innovative formulation of PS processed with vinegar (PSP) and evaluated it by comparing with the traditional decoction of PS (PSD) and non-steroidal anti-inflammatory drug (NASID) (i.e., meloxicam) in a RA Sprague Dawley rat model, which is induced with a complete Freund's adjuvant (CFA). The anti-inflammatory activities were evaluated by paw edema measurement, arthritic score, histopathological examination, pro-inflammatory cytokines (IL-1β and TNF-α) production and the whole blood viscosity. PSP treatments (249.0 mg/kg.bw) from day 14-42 alleviated paw edema (P < 0.001), arthritic index (score 0-1.5) and the inflammatory cell infiltration in the ankle joint, which may be attributed to inhibiting the production of TNF-α (P < 0.01) and IL-1β (P < 0.05) in the serum. Although PSP is with fewer efficacies than meloxicam, it outperformed traditional formulation PSD (830 mg/kg.bw) in all above mentioned metrics. Furthermore, PSP exhibited a unique effect on reducing whole blood viscosity (P < 0.05) unobserved in meloxicam intervention. The present study demonstrates that PSP showed more efficient anti-inflammatory activity than PSD in CFA-induced RA rats, possibly due to the presence of higher levels of active ingredients. Thus, PSP may be a promising therapy for anti-inflammation in RA and can be integrated with conventional treatments, particularly for long-term RA management in an integrative treatment strategy.