Systemic and local antiinflammatory effect of magnesium chloride in experimental arthritis.

Objective: Despite some knowledge gaps in scientific evidence, MgCl₂ is largely used for pain relief in musculoskeletal diseases. Mg salts were shown to provide analgesia postoperatively in orthopedic surgery and low Mg levels were linked to arthritis development and severity. We determined the anti-inflammatory activity of MgCl₂ in an acute arthritis model.

Methods: Mice received 0.1 mg/25µL Zymosan (Zy) or saline into the knees. Joint pain was evaluated using von Frey test; cell influx, and interleukin (IL)-1 level were assessed in joint lavage at 6 h. Synovia were excised for histopathology and analysis of immunoexpression of nuclear factor kappa B (NFκB) and tumor necrosis factor (TNF)-α. Groups (n = 6/group) received either 90 mg/kg MgCl₂/100 µL or saline per os (systemic) or 500 µg/25 µL MgCl₂ or saline intra-articularly (i.a.) 30 min prior to Zy.

Results: MgCl₂ given either systemically or locally significantly reduced cell influx (p = 0.0012 and p = 0.0269, respectively), pain (p = 0.0005 and p = 0.0038, respectively), and intra-articular IL-1 level (p = 0.0391), as compared to saline. Systemic MgCl₂ significantly decreased NFκB (p < 0.05) immmunoexpression, as compared to saline.

Conclusion: MgCl₂ given systemically or locally displayed anti-inflammatory activity in a severe acute arthritis model reducing cell influx, pain, and cytokine release. MgCl₂ operates at least partially via inhibiting NFκB activation. This is the first in vivo demonstration that MgCl₂ decreases cytokine release in arthritis, prompting reduction of inflammation and pain relief.