Morphofunctional Modifications of Neurocytes of the Rat Hippocampal CA3 Area after Experimental Thermal Trauma

In experiments on mature male Wistar rats, the dynamics of morphological modifications of neurocytes of the hippocampal CA3 area after a severe thermal trauma were examined. The pattern and degree of morphofunctional changes in the nerve cells depended significantly on the time interval after thermal trauma; their intensity correlated with the stages of burn disease. At stages of acute shock and early toxemia (days 1 to 7), mostly effects that could be interpreted as adaptive/compensatory reactions were observed, although initial signs of destructive changes were also obvious. At stages of late toxemia and septicotoxemia (days 14 to 21), deep irreversible destructive modifications in a considerable part of neurocytes of the hippocampal CA3 area became appreciable. The proportions of neurocytes belonging to different morphological types and values of the nucleo-cytoplasmic ratio (NCR) in such cells changed significantly. After an experimental burn, the total density of neurocytes gradually decreased, while portions of sharply hypo- and hyperchromic cells, in which NCRs underwent maximum modifications, increased. Electron microscopy of CA3 nerve cell demonstrated the development of destructive changes in the nuclei and cytoplasmic structures (degranulation of the endoplasmic reticulum, decrease in the number of ribosomes and polysomes, hypertrophy of the mitochondria with clarification of their matrix and destruction of mitochondrial cristae, and increase in the number of lysosomes). Therefore, severe thermal trauma induces significant morphofunctional modifications of neurocytes in the hippocampal CA3 area.