Effect of amino acids on cell proliferation and protein p53 expression in organotypic culture of lymphoid tissue from neonatal rats.

The effect of the larger molecular weight l-amino acids on the development of spleen explants from 1- and 21-day rats in organotypic tissue culture was studied. The amino acids asparagine, lysine, arginine, and glutamic acid inhibited the growth zone of explants of immature tissue from 1-day animals but had an opposite, stimulating, effect on mature spleen tissue of 21-day rats. Immunohistochemical analysis revealed a reciprocal correlation between the expression of the proapoptotic protein, p53, and T-cell proliferation in response to lysine, asparagine, and glutamic acid. Interestingly only arginine reduced the area of p53 expression both in explants of mature and immature spleen tissue. The ability of arginine to reduce p53 expression can be suggested as one of the mechanisms of the tumor growth stimulation.