Background: Mild hypothermia, i.e. maintenance of organ temperature by up to 8°C lower than body temperature, is a critical
strategy for exerting some functions of the cells and organs normally, and is an useful therapy for recovering properly from some diseases, including myocardial infarction, cardiac arrest, brain injury, and ischemic stroke. Nevertheless, there were no focusses so far on organ temperature
and potential responses of gene expression to organ temperature in organs of homeothermic animals that survive under normal conditions.
Objective: The present study aimed to assess organ temperature in homeothermic animals and evaluate the effect of their organ temperature
on the expression of the cold shock protein RNA binding motif protein 3 (RBM3), and to gain insights into the organ temperature-mediated
regulation of RBM3 gene transcription via Nuclear factor β-light-chain-enhancer of activated B cells (NF-κB) p65, which had been identified as a transcription factor that is activated by undergoing the Ser276 phosphorylation and promotes the RBM3 gene expression during
mild hypothermia.
Methods: We measured the temperature of several organs, where RBM3 expression was examined, in female and male mice. Next, in male
mice, we tested NF-κB p65 expression and its Ser276 phosphorylation in organs that have their lower temperature than body temperature
and compared them with those in organs that have their temperature near body temperature.
Results: Organ temperature was around 32°C in the brain and reproductive organs, which is lower than the body temperature, and around
37°C in the heart, liver, and kidney, which is comparable to the body temperature. The expression of RBM3 was detected greatly in the
brain and reproductive organs with their organ temperature of around 32°C, and poorly in the heart, liver, and kidney with their organ temperature of around 37°C. In accordance with the changes in the RBM3 expression, the NF-κB p65 Ser276 phosphorylation was detected
more greatly in the testis and brain with their organ temperature of around 32°C, than in the heart, liver, and kidney with their organ temperature of around 37°C, although the NF-κB p65 expression was unchanged among all the organs tested.
Discussion: Our data suggested that organ temperature lower than body temperature causes the expression of RBM3 in the brain and reproductive organs of mice, and that lower organ temperature causes the NF-κB p65 activation through the Ser276 phosphorylation, resulting in
an increase in the RBM3 gene transcription, in the brain and reproductive organs of mice.
Conclusion: The study may present the possibility that organ temperature-induced alterations in gene expression are organ specific in homeotherms and the possibility that organ temperature-induced alterations in gene expression are transcriptionally regulated in some organs
of homeotherms.
The uptake of radioactive copper by the brain and other tissues of the developing rat