Cerebellar gene expression following human traumatic brain injury

Gene expression of specific brain biomarkers offers the possibility of shedding light on the difficult molecular pathways of traumatic brain injury (TBI) and may be useful to estimate the age of trauma. Gene expression rates of cerebellar injuries are not yet sufficiently established. In 12 cases (mean age 42 years) of TBI including a pathological change in cerebellum (with known survival times ranging from immediate death to 96 h), brain tissue samples from different brain regions were analyzed with real-time polymerase chain reaction (PCR) for expression of caspase-3, tyrosine kinase receptor B (TrkB), S100B, and glial fibrillary acidic protein (GFAP) mRNA. The pH was measured to gain information about a possible correlation to RNA degradation. For comparison, corresponding brain regions were arranged from control samples of subjects that died from sudden death. We found a correlation between pH and the degradation of RNA in samples from the contralateral site, where the samples with degraded RNA have a lower pH (p<0.05). For short survival times, the expression changes of caspase-3 (p<0.05) and the expression changes of TrkB (p<0.1) in the cerebellum show a significant increase compared to the controls. The cerebellar gene expression changes seem to occur much faster and stronger compared to the other investigated regions, in particular the cerebral trauma site. These findings could make the cerebellum an important target area to study the expression changes after TBI.