局灶低温治疗大鼠创伤性脑水肿及对乳酸的影响

目的：观察局灶低温治疗对大鼠脑创伤后脑水肿的作用和对乳酸含量的影响。方法：SD大鼠168只，随机分成6组，每组28只：A组，假手术对照组；B组，脑外伤模型对照组；C组，0℃水局灶低温治疗组；D组，10℃水局灶低温治疗组；E组，20℃水局灶低温治疗组；F组，25℃水局灶低温治疗组。除A组外各组动物均按Feeney方法制作重度脑创伤模型，B组伤后不予治疗，C，D，E，F 4组伤后30 min开始给予局灶低温治疗，20～30 min局灶脑温降至3l℃并维持3 h。所有动物分别于伤后l，3，5，7 d处死，取伤区脑组织测水含量及乳酸含量。结果：B组各时间点脑组织水含量和乳酸含量比A组升高(1，3，5，7 d组均P<0.05)。C，D，E，F组与B组相比，C组水含量和乳酸含量无统计学意义(P>0.05)，其余3组均降低(P<0.05)。局灶低温各组间相比，C组水含量、乳酸含量最高(P<0.05)。结论：对大鼠脑外伤后脑水肿，0℃水局灶低温治疗无效果，10℃，20℃，25℃水局灶低温治疗有效，以20℃和25℃水局灶低温的效果更好。减少乳酸堆积、缓解酸中毒可能是其作用机制之一。

Effect of focal hypothermia on traumatic brain edema and the content of lactic acid in the brain tissue in rats

ABSTRACT: Objective To investigate the effect of focal hypothermia (LH) on traumatic brain edema and the content of lactic acid in rat brain tissue. METHODS: One hundred and sixty-eight adult SD rats were randomly divided into 6 groups: Group A, sham injury group; Group B, traumatic brain injury controlled group; Group C, treated by LH with water at 0 degree C; Group D, treated by LH with water at 10 degrees C; Group E, treated by LH with water at 20 degrees C; Group F, treated by LH with water at 25 degrees C. All rats except those in Group A were subjected to traumatic brain injury (TBI) with Feeney's method. LH began for animals in Group C - F 30 minutes after the TBI. Regional brain temperature reached the target temperature of 31 degrees C within 20-30 minutes and maintained for 3 hours. Each group was divided into 4 sub-groups by investigating the duration after the TBI: 1, 3, 5 or 7 day sub-group. At the end of investigation, the rats were killed and water content (WC) and concentration of lactic acid (LA) in the brain tissues were measured. RESULTS: Compared with Group A, WC and LA of Group B increased significantly at each investigation duration (P < 0.05). Compared with Group B, WC and LA of Group C did not change (P > 0.05), but those of Group D, E, and F decreased significantly (P < 0.05). WC and LA of group C were the highest among Group C - F. CONCLUSION: Focal hypothermia with water of 10 degrees C, 20 degrees C, and 25 degrees C but not 0 degrees C has some effect on traumatic brain edema and the temperature at 20 degrees C and 25 degrees C are the better. The mechanism of focal hypothermia may be associated with inhibiting acidosis of lactic acid.