Correlation between heat shock protein 70 expression in the brain stem and sudden death after experimental traumatic brain injury

Objective: The aim of this study was to determine the patterns of heat-shock protein 70 (HSP70) biosynthesis following traumatic brain injury, and observe the effect of HSP70 induction on the function of the vital center in the brain stem. Methods: Rat models of sudden death resulted form traumatic brain injury were produced, and HSP70 expression in the rat brain stem was determined by immunohistochemistry, the induction of HSP70 mRNA detected by RT-PCR. Results: The level of HSP70 mRNA was prominently elevated in the brain stem as early as 1 5 min following the impact injury, while HSP70 expression was only observed 3 to 6 h after the injury. It was also observed that the levels of HSP70 mRNA but not the protein were elevated in the brain stem of sudden death rats. Conclusion: The synthesis of HSP70 was significantly enhanced in the brain stem following traumatic injury, and the expression of HSP70 is beneficial to eliminate the stress agents, and to sustain the cellular protein homeostasis. When the injury disturbs the synthesis of HSP70 to disarm the protective mechanism of heat-shock proteins, dysfunction of the vital center in the brain stem, and consequently death may occur. Breach in the synchronization of HSP70 mRNA-protein can be indicative of fatal damage to the nerve cells.