DNA microarray analysis of the mouse adrenal gland for the detection of hypothermia biomarkers: potential usefulness for forensic investigation.

We analyzed the adrenal gland transcriptome of mice killed by hypothermia using DNA microarray technology. A total of 4051 significantly expressed genes were identified; 2015 genes were upregulated and 2036 were downregulated.The FBJ osteosarcoma oncogene was the most upregulated,whereas stearoyl coenzyme A desaturase 3 was the most downregulated. Validation by quantitative polymerase chain reaction revealed that results obtained by both methods were consistent. In the gene set analysis, significant variations were found in nine pathways, and we suggest that transforming growth factor β and tumor necrosis factor α would be involved in the pathogenesis of hypothermia. Gene functional category analysis demonstrated the most overexpressed categories in upregulated and downregulated genes were cellular process in biological process, binding in molecular function, and cell and cell part in cellular component. The present study demonstrated acute adrenal responses in hypothermia, and we suggest that understanding adrenal mRNA expression would be useful for hypothermia diagnosis. Furthermore, the present microarray data may also facilitate development of immunohistochemical analysis of human cases. In forensic practice, the combination of macroscopic and microscopic observations with molecular biological analyses would be conducive to more accurate diagnosis of hypothermia. Although this study is aimed at forensic practice, the present data regarding more than 20,000 genes of the adrenal gland would be beneficial to inform future clinical hypothermia research. From the viewpoint of adrenal gene activity, they could contribute to elucidating the pathophysiology of hypothermia.