Two experiments were performed to clarify the effects of balneotherapy on platelet glutathione metabolism. One experiment, in which healthy men were subjected to water immersion at temperatures of 25°C, 36°C, and 42°C for 10min, showed that the level of platelet lipid peroxides (LPO) tended to increase at 25°C and 42°C, suggesting the presence of oxidative stress at these temperatures. When an antioxidative defense system was induced at these temperatures, the levels of platelet glutathione (GSH), glutathione peroxidase (GPX) and glutathione reductase (GR) activities increased. The other experiment, in which 4 weeks of balneotherapy was applied to type II (non-insulin-dependent) diabetic patients, showed that the level of GSH on admission correlated well with that of fasting plasma glucose (FPG, r=0.692, p<0.050). After 4 weeks of balneotherpy, the level of GSH increased (p<0.01) in well-controlled patients (FPG<150mg/dl) and decreased (p<0.05) in poorly controlled patients (FPG≥150mg/dl), There was a negative correlation between GPX activities and the level of FPG (r=-0.430, p<0.05). After the balneotherapy, the activity increased in five patients, decreased in three patients, and showed no changes in four patients.
These results indicate that, in diabetic patients, 1) platelet GSH synthesis is obviously induced in response to oxidative stress, 2) lowered GPX activities suggest an impaired antioxidative defense system, and 3) platelet glutathione metabolism was partly improved by 4 weeks of balneotherapy but depended on the control status of plasma glucose levels. From these findings, we conclude that 1) patients whose platelet antioxidative defense system is damaged such as those with diabetes mellitus should not take hot or cold bath, and that 2) balneotherapy improves platelet glutathione metabolism, leading to normalization of platelet aggregability.
