The neuronal protective effects of local brain cooling at the craniectomy site after lateral fluid percussion injury in a rat model

Background: The aim of the present study is to investigate whether local brain cooling at the craniectomy site causes attenuation of traumatic brain injury (TBI) induced by fluid percussion injury (FPI). Methods: Anesthetized male SpragueeDawley rats were divided into two major treatment groups. Immediately after the onset of fluid percussion TBI, a craniectomy window of 6 × 8 mm was made at the right parietal, and a cold water bag (0°Ce1°C or 5°Ce6°C) was applied locally for 30 min. Additional groups of rats were used as craniectomy and craniectomy FPI controls. Physiological parameters, such as brain and colonic temperature, mean arterial pressure, and heart rate, were monitored during FPI. Functional motor outcomes were evaluated using the inclined plane test (maximal grasp angle). Cellular infarction volume was calculated using triphenyltetrazolium chloride staining. Apoptosis and neuronal markerepositive cells in the cortex were measured by immunofluorescence staining. All functional and morphologic parameters were assessed 72 h after injury. Results: Compared with the craniectomy FPI control groups, the groups treated with 5°Ce6°C local cold water therapy showed significant attenuation of the FPI-induced motor deficits, weight loss, and cerebral infarction but no effect on colonic temperature. The FPI-induced apoptosis and neuronal loss were also significantly reduced by local cooling. Conclusions: Our results suggest that local cooling with 5°Ce6°C cold water therapy may ameliorate TBI in rats by reducing infarction volume, neuronal cell loss, and apoptosis, resulting in improved functional outcome. We propose that the use of local cooling at the craniectomy site after FPI might have clinical benefits in the future.