RESUMO
<p><b>OBJECTIVE</b>To investigate the expression of Caspase-3 and Hsp70 in rabbits after severe traumatic brain injury (TBI) and to explore the feasibility of its application in estimation of injury time in forensic medicine.</p><p><b>METHODS</b>A rabbit model of heavy TBI was developed by high velocity impact on the parietal bone with an iron stick. Totally 8 healthy adult New Zealand white rabbits were randomly divided into control group (n equal to 2) and injury group (n equal to 6). Four hours after injury, tissue specimens from the parietal lobe, temporal lobe, occipital lobe, cerebellum and brainstem were harvested to detect the expression of Hsp70 and Caspase-3 by immunohistochemistry. Besides, the gray values of cells positive for Hsp70 and Caspase-3 were analyzed with an image analyzer.</p><p><b>RESULTS</b>Immunohistochemistry staining demonstrated a low level of Caspase-3 and Hsp70 expression in normal control group. While in injury group, both the Caspase-3 and Hsp70 expression was significantly elevated (P less than 0.05). Positive cells gathered around the lesion focus. Occipital lobe and cerebellum had fewer positive cells while temporal and brainstem had the fewest.</p><p><b>CONCLUSION</b>The expression of Caspase-3 and Hsp70 at an early stage following severe TBI is characteristic and can be applied to estimate the time of injury.</p>