Effect of lactic acid on the survival rate of cultured rat cortex neurons in vitro

AIM To prob the effect of lactic acid on the survival rate of cultured rat cortex neurons. METHODS Neurons in primary culture were divided into two parts: (1) Neurons were cultured in physical medium, which was rendered acidotic by addition of lactic acid in rising concentrations. 0 mmol/L, 5 mmol/L, 10 mmol/L, 20 mmol/L, pH range were 7.35, 7.15, 6.95, 6.00. (2) The cells were cultured in physical medium in the presence of lactic acid at increasing concentrations, respectively including lactate 0 mmol/L, 5 mmol/L, 10 mmol/L, 20 mmol/L. They were regulated to maintain pH 7.35. MTT was used to detect the neurons survival rate. RESULTS Neurons survival rate significantly decreased with the pH decrease compared with the group pH 7.35. Different lactate concentrations can also reduce the neurons survival rate apparently compared with the group included no lactate. The survival rate of groups pH 7.15 and pH 6.95 were lower than the group in which the lactate concentration was 5 mmol/L and 10 mmol/L. CONCLUSION It has close relation between pH decrease induced by lactate and neurons survival rate. Lactate can also exert neuron toxicity independently without pH decrease.