Polyphenol-rich Sorghum bicolor supplement exhibits anti-nociceptive activity and protective effects against pathological changes associated with complete Freund's adjuvant induced arthritis in rodents

Introduction

Arthritis is a common inflammatory joint disease; causing severe pain, anxiety, and depression. Sorghum bicolor L. Moench (Pocaeae) is used for treating cough, asthma, and arthritic pain in Traditional Chinese Medicine (TCM). This study evaluates the anti-nociceptive and anti-arthritic effects of the polyphenol-rich Sorghum bicolor supplement (SBS) in rodents.

Methods

The anti-nociceptive activity of SBS was assessed using hot plate, acetic acid mouse writhing, and formalin-induced paw licking tests in mice. In the arthritis study, rats received SBS (50, 100, and 200 mg/kg p.o) for 28 days. Thirty minutes after treatment on days, 1 and 20, rats received intra-articular injection of Complete Freund's adjuvant (CFA) for arthritis induction. Arthritic scores and paw edema were determined before assessing motor function, anxiety, depression, hyperalgesia and allodynia on day 28. Lipid profiles were determined, and ankle and brain tissues were analyzed for oxidative stress and inflammatory biomarkers, alongside histopathological studies.

Results

SBS reduced nociceptive responses induced by noxious heat, acetic acid and formalin in mice. In CFA-injected rats, SBS decreased paw volume and arthritic scores, and increased pain thresholds to thermal, cold, and mechanical stimuli. The SBS reduced motor activity, anxiety and depression, and improved serum lipid profiles in arthritic rats. It further modulated oxidative stress, pro-inflammatory cytokines, nuclear factor kappa (NF-kB), apoptotic markers, nuclear factor erythroid 2-related factor 2 (NRF2), glutamic acid decarboxylase (GAD) and brain-derived neurotrophic factor (BDNF) in CFA-treated rats. SBS produced histopathological improvements in joint tissues of arthritic rats.

Discussion

This study revealed that SBS exhibited anti-nociceptive activity in mice and reduces inflammation, hyperalgesia, anxiety and depression in CFA-arthritic rats. The ability of SBS to modulate key biomarkers such as pro-inflammatory cytokines, NF-κB, caspases, Nrf2, BDNF, and GAD highlights its multifaceted approach in addressing both the physical and psychological aspects of arthritis, providing a comprehensive therapeutic strategy, justifying its use in TCM for this debilitating condition.