OBJECTIVETo investigate the influence of therapeutic bloodletting at Jing-well points and hypothermia on acute cerebral edema after traumatic brain injury (TBI) in rats.

METHODSSeventy-five SD rats were randomly divided into sham-operation group (Sham), TBI group (TBI), bloodletting group (BL), mild-induced hypothermia group (MIH), and bloodletting plus MIH group (BL + MIH) (n = 15). The model of TBI was established by electric controlled cortical impactor (eCCI). The rats of BL group were bloodletting at Jing-well points immediately after injury, twice daily. While the MIH group was settled on a hypothermia blanket promptly after TBI for 6 hours, so that the temperature dropped to 32 degrees. Each of measurement was performed after 48 hours. Magnetic resonance imaging (MRI) was used to evaluate the dynamic impairment of cerebral edema after TBI (n = 3). In addition, mNSS score, measurements of wet and dry brain weight, and Evans Blue assay were performed to investigate the neurologic deficit, cerebral water content (n = 8), and blood-brain barrier permeability (BBB), (n = 4), respectively.

RESULTSMRI analysis showed that the cerebral edema, hematoma and midline shifting of rats in TBI group was more serious than other treatment group. Meanwhile compared with TBI group, the mNSS scores of every treatment group were meaningfully lower (all P < 0.05). Furthermore, treatment with BL+ MIH group was superior to the separated BL and MIH group (all P < 0.01). In addition, brain water content of each intervention group reduced to varying degrees (all P < 0.05), especially that of MIH group and BL + MIH group (P <0.01). BBB permeability of each treatment group was also significantly improved (all P < 0.01), and the improvement in MIH group and BL + MIH group was much better than the BL alone group (P < 0.05, P < 0.01).

CONCLUSIONOur major finding is that bloodletting at Jing-well points and MIH can reduce cerebral edema and BBB dysfunction and exert neuroprotective effects after TBI. The results suggest that the combination of BL and MIH is more effective than other treatment being used alone.