Accumulation of calcium in the brain following head trauma

Previous studies have reported accumulation of calcium (Ca) in brain tissue of injured or ischaemic experimental animals. In the present study, head trauma (HT) was induced in the left hemisphere of rats which were subsequently sacrificed 15 min, 1, 2, 4, 24 or 48 h later. Their brains were analysed for oedema formation by the determination of specific gravity (SG), using linear gradient columns, and water content, by dry to wet weight ratio. Total tissue Ca content was measured by atomic absorption spectroscopy. These values, in both the injured and contralateral hemispheres were compared with values obtained from sham-operated rats. Specific gravity of the contused hemisphere was lower than that of the contralateral hemisphere or sham and its water content was higher, at all time points studied. Calcium content was significantly higher in the contused grey matter at 1 h, and in the grey and white matter of both hemispheres at 24 and 48 h after HT. Statistical analysis revealed excellent correlation (cc = 0.65, p less than 0.001) between Ca levels and water content in the grey matter, whenever Ca concentrations were elevated (1, 24 and 48 h). These findings suggest that in the late phase of the post-HT period, Ca accumulation might play a role, along with other mediators, in the development of brain oedema after HT.