MECHANISMS OF ACTION OF BALNEOTHERAPY IN RHEUMATIC DISEASES: THE SCIENTIFIC EVIDENCE

Abstract

Balneotherapy represents a treatment widely used in many rheumatic diseases (RD). The mechanisms by which immersion in mineral or thermal water ameliorates RD are not fully understood. The beneficial effect of balneotherapy has probably a multifactorial nature.Buoyancy, immersion, resistance and temperature all play important roles. According to the gate theory, pain relief may be due to the pressure and temperature of the water on skin; hot stimuli may influence muscle tone and pain intensity, helping to reduce muscle spasm and to increase the pain threshold. Mud-bath therapy increases plasma β-endorphin levels and secretion of corticotrophin, cortisol, growth hormone and prolactin. It has recently been demonstrated that thermal mud-bath therapy induces a reduction in circulating levels of Prostaglandin E2 (PGE2), Leukotriene B4 (LTB4), Interleukin-1β (IL-1β) and Tumour Necrosis Factor-α (TNF-α), important mediators of inflammation and pain. Furthermore, balneotherapy has been found to cause an increase in Insulin-like Growth Factor-1 (IGF1), which stimulates cartilage metabolism, and Transforming Growth Factor-β (TGF-β). Beneficial anti-inflammatory and anti-degenerative effects of mineral water were confirmed in chondrocytes cultures, too. It has been also shown the positive action of mud-packs and thermal baths on the oxidant/antioxidant system, with a reducing release of reactive oxygen (ROS) and nitrogen (RNS) species. Overall, thermal stress has an immunosuppressive effect. Many other non-specific factors may also contribute to the beneficial effects observed after balneotherapy in some RD, including effects on cardiovascular risk factors and changes in the environment, pleasant surroundings and the absence of work duties.