The assessment of brain injury with measurement of calcium fluorescent intensity of a vital brain slice

Abstract

Retrograde cerebral perfusion (RCP) is one of cerebral protection methods during deep hypothermic circulatory arrest (DHCA). However, the mechanism is unclear. In this study with laser confocal scanning microscope (LCSM), calcium fluorescent intensity of vital brain slice was compared between RCP and DHCA group. Sixteen swine, weighing from 19 - 20 kg and supplied by Beijing College of Agriculture, were used for the experiment. After 90 min of DHCA or RCP through the superior vena cava, the animals were rewarmed for 120 min. Through tentorium of the cerebellum and enucleation of the eyeball, vital brain slices (cerebellula and retina) were obtained and fluorescein labeled in artificial cerebrospinal fluid containing 5 μmol/L Fluo-3/AM (fluoresence probe). The calcium fluorescent intensity was examined by LCSM. The results indicated that calcium fluorescent intensity of vital brain slice was lower in the RCP group (cerebellula, 9.16 ± 3.98; retina, 21.48 ± 14.27) than that in the DHCA group (cerebellula, 31.97 ± 20.59; retina, 44.07 ± 21.01) (p < .05). More moderate and severe eosinophilic degeneration was found in the DHCA group than in the RCP group (p < .05) through morphological examination. The statistical analysis also indicated the calcium fluorescent intensity of the vital brain slice was correlated with the level of moderate and severe eosinophilic degeneration of thee neuron (r = 0.86, p < .05). So "calcium overload" contributes to the injury of neuron after DHCA. RCP is able to attenuate "calcium overload," which has the effect of cerebral protection.