ORIGINAL PAPER The effect of monosodium glutamate on the apoptosis of rat thymocytes and Bcl-2 protein expression

Introduction: Monosodium glutamate (MSG) is the sodium salt of glutamic acid widely spread in modern nutrition. Numerous recent studies have shown the existance of glutamic receptors on different non-neuronal cells, which among others also include lymphocytes and thymocytes. However, it has not yet been precisely established what modulatory effect is created by the activation of these receptors on the immune system cells. Material and methods: We have evaluated the effect of different MSG doses on the intensity of apoptosis of rat thymocytes, as well as the expression of their antiapoptotic protein, Bcl-2. Apoptosis was detected using the Annexin V-FITC apoptosis detection kit and cells were analysed using a flow cytometer. Expression of Bcl-2 was determined with flow cytometry using respective monoclonal antibodies. Results: The current study results demonstrate that different MSG doses significantly increase the intensity of thymocyte apoptosis in a culture. Also, the expression of Bcl-2 proteins in the thymocyte culture, after it has been cultivated with different MSG doses, is significantly reduced. Conclusions: The results presented in our study indicate that different MSG doses significantly modulate the intensity of the apoptotic thymocyte process in a culture, and that one of the possible ways through which MSG induces apoptosis is the reduction of Bcl-2 protein expression.