In situ hybridization histochemistry of Bax and Bcl-2 mRNA expression following lateral fluid-percussion brain injury. Representative bright field photomicrographs illustrating cellular localization of Bax mRNA (A,C) and Bcl-2 mRNA (B,D) in the temporal cortex of sham-injured rat brains (A,B), and at 24 h (C,D) following brain injury. Note accumulation of grains corresponding to Bax mRNA over cell bodies in the cortex at 24 h post-injury (C). Constitutive expression of Bcl-2 mRNA was observed in cortical cells in sham-injured rats (B), which did not appear to change at 24 h post-injury (D). Bar = 170 μm.