Effect of Borax on Glutathione Levels in Human Red Blood Cells in Vitro

Sodium tetraborate or borax is used as a preservative in food and it is toxic to humans depending on dosage. The target organs of borax toxicity include the central nervous system, kidney and liver, and borax can be accumulated in the blood circulation. The aim of this study was to evaluate the effect of borax on human red blood cells (RBCs) of both normal and chronic renal failure (CRF) patients by determining glutathione (GSH) levels and plasma borax levels. Normal packed RBCs were incubated with borax at 0, 0.33, 0.65, 1.30, and 2.60 μM and measured GSH levels to identify the maximal dose effect. Then RBCs of both normal and CRF groups were incubated in borax solution (at 1.3 μM, which was the maximal effect dose) at 0, 60, 120, and 180 minutes and determined for GSH levels by the dithiobisnitrobenzoic (DTNB) method. Plasma borax was measured by using the carminic method in 10 normal and 17 CRF patients. The mean GSH level in normal subjects was found at 53.90±9.41 mg/dL, and 63.41±13.64 mg/dL (p>0.05) in CRF patients. GSH levels showed no significant change between healthy and CRF patients (p>0.05) after incubating RBCs with borax solution at different times. The plasma borax levels were not significantly different (p>0.05) between healthy subjects (3.34±1.05 mg/L) and CRF patients (3.07±1.34 mg/L). Borax may not be a risk factor of renal failure. It could be concluded that borax is not an oxidant for human RBCs in vitro. Chiang Mai Med Bull 2006;45(3):93-100.