Investigation of possible cerebral effects of endogenous hyperthermia and effectiveness of therapeutical agents against this damage in infant rat model

Hyperthermia may cause pathological changes in all systems and organs including the brain. The present study represents the second part (endogenous hyperthermic cerebral damage) of our research which investigates endogenous and exogenous hyperthermic cerebral damage. Our target is to the second part of our study which investigates endogenous and exogenous hyperthermic cerebral damage. We investigated the consequences of lipopolysaccharide (LPS)-induced hyperthermia related neuronal damage and, effects of therapy methods (hypothermia, paracetamol, dexametasone, diclofenac) which used in pediatric practice in infant rats. Possible neural damage was evaluated by examining the healthy, necrotic and apoptotic cells and heat shock proteins (HSP, HSP 27 and HSP 70) in the cerebral cortex, cerebellum and hypothalamus. Convulsions were observed in (15/36, 41%) of the animals, and five of the (5/15, 33 %) convulsion experienced infant rats (at 41 °C) were died. In the three regions of brain hyperthermic damage; ( i ) causes significant increase in cerebral cortex, cerebellum, hypothalamic necrotic and apoptotic cells (p<0.05), (ii) causes significant decrease in healthy neurons of cerebral cortex (p<0.05), (iii) did not cause any significant change in the rates of HSP 27 and 70 (p>0.05) in all three neuronal areas investigated. Among to the applied therapy methods ; (i) Paracetamol caused increase in the ratio of HSP 70 in cerebral cortex and hypothalamus, and also increase in healthy cells in hypothalamus and decrease in the necrotic cells in hypothalamus (p<0.05) (positive effect of paracetamol), (ii) except diclofenac the other therapy methods (hypothermia, paracetamol and dexametasone) decreased the rate of apoptotic cells (p<0.05).In conclusion, results of the present study show that hyperthermia causes area-dependent damages in neuronal tissues in the brain, and recovery responses to the different treatment modalities are also different.Key words: Lipopolysaccharide (LPS), hyperthermia, rat, brain, treatment