Coordinated expression of pro- and antiapoptotic proteins in the hippocampus of neonatal rats

We studied the contents of the apoptotic proteins Bcl-XL, Bax, and intact and active forms of caspase-3 using the immunoblot method in the hippocampus and brainstem of 3-day-old rat pups. The expression of pro- and antiapoptotic proteins in the regions of the developing brain demonstrates individual variability with a variation coefficient ranging from 10 to 40%. In the brainstem, a structure with a low intensity of apoptosis at this period of ontogeny, correlations between the expression levels of these proteins were not significant. However, in the hippocampus we observed a significant positive correlation between the levels of expression of the proapoptotic proteins Bax and the active form of caspase-3 (r = +0.653). The levels of these proteins significantly negatively correlated with the content of the antiapoptotic protein Bcl-XL (r = −0.651 and −0.740, respectively). Our data suggest coordinated expression of the apoptotic cascade proteins in the hippocampus, a brain structure with a high intensity of elimination of excessive cells during early postnatal ontogeny.