烧伤应激大鼠脑组织代谢物的多体素磁共振波谱动态分析

Dynamic study of magnetic resonance spectrum of brain metabolism of rats after burn stress

目的采用多体素磁共振波谱(MRS)定量分析烧伤应激大鼠模型脑额叶及尾状核组织代谢物,提高对严重烧伤应激早期脑损害的认识。方法选用35只健康雄性SD大鼠,随机原则分成7组:对照组及烧伤后3、6、12、18、24及48 h组,每组5只。烧伤各组采用改良的walker&Mason标准大鼠烧伤模型制备方法,建立20%深Ⅱ度大鼠烧伤应激模型,在相应时间点行大鼠颅脑多体素磁共振波谱检查,主要观测大鼠颅脑双侧额叶及尾状核Cho/Cr、NAA/Cr比值。结果与对照组相比,烧伤组大鼠脑组织和NAA/Cr值水平显著低于对照组,而Cho/Cr值水平显著高于对照组(P<0.01);不同烧伤时间之间大鼠脑组织NAA/Cr值、Cho/Cr值差异存在统计学意义(P<0.01);大鼠额叶NAA/Cr值水平显著低于尾状核NAA/Cr值水平(P<0.01),额叶Cho/Cr值水平显著高于尾状核Cho/Cr值水平(P<0.01);大鼠左侧和右侧脑组织NAA/Cr值水平差异无统计学意义(P=0.65),大鼠右侧脑组织Cho/Cr值水平显著高于左侧水平(P=0.018)。结论大鼠烧伤应激早期出现脑损害,多体素磁共振波谱能早期观测到多个代谢物指标异常,并部分呈现一定的规律性。

Objective Magnetic resonance spectroscopy （MRS） was applied to analyze the metabolism of the frontal lobe and caudate nucleus of rats underwent severe burn stress, so as to improve the understanding of early brain damage caused by severe burn. Methods A total of 35 healthy male Sprague-dawley （SD） rats weighted 250 to 300 g were randomly divided into 7 groups, including the control group and 3, 6, 12, 18, 24 and 48 hour burn group post-burn stress, with 5 rats in each group. The modified standard rat burn model proposed by Walker and Manson was established with second-degree burn wound covering 20 percent of body surface. The rats in each group were examined by MR1 at corresponding time points to observe change of MRS. The potential change of Cho/ Cr and NAA/Cr of bilateral frontal lobe and caudate nucleus were recorded. Results （ 1 ） Compared with the con- trol group, the NAA/Cr of post-burn rats were significantly reduced, while Cho/Cr was significantly increased （P 〈 0.01, respectively）. （2）Significant differences in NAA/Cr, Cho/Cr values were observed among different sampling time points （P 〈 0.01, respectively）. （3）The NAA/Cr value of the frontal lobe was significantly lower than cau- date nucleus （P 〈 0.01 ）. The Cho/Cr value of frontal lobe was significantly higher than caudate nucleus （P 〈 0.01 ）. The NAA/Cr value of the left and right sides of brain were similar, and the Cho/Cr value of the right brain was significantly higher than the, left side （P = 0.018）. Conclusions MRS can detect the abnormality of burn stress-induced rat brain damage in the early stage, with certain regularity.