PATTERNS OF HEAT-SHOCK-PROTEIN-70 BIOSYNTHESIS FOLLOWING HUMAN TRAUMATIC BRAIN INJURY

Heat-shock protein 70 (hsp70) is activated upon cellular stress/injury and participates in the folding and intracellular transport of damage d proteins, The expression of hsp70 following CNS trauma has been spec ulated to be part of a cellular response which is involved in the repa ir of damaged proteins, In this study, we measured hsp70 mRNA and prot ein levels within human cerebral cortex subjected to traumatic brain i njury. Specimens were obtained during routine neurosurgery for trauma and processed for Northern mRNA and Western protein analysis, The larg est increase in hsp70 mRNA levels was detected in trauma tissue obtain ed 4-6 h following injury. By 24 h, hsp70 mRNA levels were similar to nontrauma comparison tissues, hsp70 protein expression exhibited its g reatest increases at 12-20 h post-injury, Immunocytological techniques revealed hsp70 protein expression in cells with neuronal-like morphol ogy at 12 h after injury, These results suggest a role for hsp70 in hu man cortex following TBI, Moreover, since the temporal induction patte rn of hsp70 biosynthesis is similar to that reported in the rodent, ou r observations validate the importance of rodent brain injury models i n providing useful information directly applicable to human brain inju ry.