Affiliations: Department of Neurosurgery, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467, Japan
Note: [] Correspondence to: Hiroyuki Katano, M.D., Department of Neurosurgery, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467, Japan. Tel.: +81 52 853 8286; fax: +81 52 851 5541
Abstract: Immediate early gene (IEG) mRNA induction by cryogenic injury was examined using an in situ hybridization approach and the results compared with the heat shock protein mRNA expression. Hybridization signals for c-fos and c-jun mRNA were found after 30 min in the ipsilateral cortex, the hippocampal dentate granule cells and the piriform cortex, c-jun mRNA was also detected in the contralateral dentate gyrus and the piriform cortex, but was less extensive. Return to baseline values was observed at the 24 h time point. Peak induction, with silver grains observed mainly over the neurons on emulsion autoradiograms, was demonstrated in all cases 30 min to 1 h post-injury. In contrast, only slight hsp70 mRNA expression by the neurons surrounding the cold-injured site could be detected by microautoradiography, at 6 h following the trauma. The results indicate that cryogenic brain injury induces IEGs in a similar way to mechanical modes of injury such as lateral fluid percussion, but that hsp70 mRNA is hardly expressed, implying the possible existence of differences in stress response pathways.
Keywords: cryogenic brain injury, immediate early genes, heat shock protein, c-fos, c-jun, hsp70, in situ hybridization
