“…Membranes were prehybridized for 4 h at 68°C in rapid hybridization buffer (Amersham, Arlington Heights, IL) and then incubated overnight at 68°C in hybridization buffer containing [ 32 P]DNA probes (1 ϫ 10 8 cpm) for HO-1, Nrf2, or 18S mRNA. DNA probes were generated by RT-PCR and labeled with [ 32 P]dCTP using a random priming kit (Amersham, Arlington Heights, IL) (28). After hybridization, membranes were washed and exposed to X-ray film at Ϫ70°C, and HO-1 expression was quantified by scanning densitometry and normalized with respect to 18S rRNA.…”