1H磁共振波谱无创检测手术创伤前后新西兰兔后肢肌肉谷氨酰胺、谷氨酸的总含量

目的评价1H磁共振波谱(MRS)无创检测手术创伤引起的骨骼肌内谷氨酰胺(Gln)、谷氨酸(Glu)代谢改变的可行性。方法建立新西兰兔手术创伤模型15只,在术前和术后第2天应用1HMRS扫描后肢肌肉,同时采集血样和肌肉活检标本待测。MRS数据采集包括Gln、Glu混合物(Glx)和总肌酸(TCr)的峰高和峰下面积值,比较二者稳定性;选择较稳定者,以Glx/TCr比值作为反映新西兰兔后肢肌肉内Glx含量的指标;观察该指标在手术前后的变化,并与传统氨基酸分析方法反相高效液相色谱法(RP-HPLC)检测血浆、肌肉组织内游离Gln、Glu浓度变化相比较,评价MRS无创检测手段的可行性。结果MRS检测时峰高比峰下面积稳定;Glx/TCr峰高比值的变异系数为(15·62±9·87)%;Glx/TCr峰高比值术后第2天比术前显著下降(P<0·05,P<0·01);术后第2天血浆和肌肉组织内游离Glx浓度与术前相比,差异均无显著性。结论MRS检测指标与RP-HPLC测定指标在反映手术创伤对骨骼肌内Glx代谢的影响时具有一致的结果;MRS用于骨骼肌内Gln、Glu代谢研究是可行的。

Noninvasive quantification of glutamine and glutamate in skeletal muscles of perioperative rabbits with proton magnetic resonance spectroscopy

OBJECTIVE: To evaluate the feasibility of noninvasive quantification of the metabolic changes of glutamine (Gln) and glutamate (Glu) in the skeletal muscles caused by abdominal surgery with proton magnetic resonance spectroscopy (MRS). METHODS: Abdominal surgery were performed on 15 healthy Zelanian rabbits. MRS data, blood specimens, and muscular tissues were obtained on the day before surgery and the second day after surgery. MRS data included peak amplitude and peak area of Gln + Glu (Glx) and total creatine (TCr). The reproducibility of peak amplitude with peak area was compared and the better one was chosen to calculate the ratio of Glx to TCr. Free Gln and Glu concentrations in serum and muscles were analyzed by reversed phase high-performance liquid chromatography (RP-HPLC). The results of MRS were compared with those of RP-HPLC to evaluate the feasibility of MRS application in Gln and Glu metabolism. RESULTS: Peak amplitude had better reproducibility than peak area under our conditions. The coefficient of variation (CV) of the ratio of the amplitude of Glx to TCr was (15.62 +/- 9.87)%. The ratio of the amplitude of Glx to TCr significantly decreased on the second day after surgery (P <0.05, P <0.01). The mean free Glx concentrations in both the serum and the muscles different were not significant between on the second day after surgery and on the day before surgery. CONCLUSIONS: The results of MRS application in reflecting the effects of surgical trauma on muscular Glx metabolism are consistent with those of RP-HPLC. It is feasible to apply MRS in the study of muscular Gln and Glu metabolism.