1H-MRS定量分析糖尿病大鼠腓肠肌代谢物早期评估糖尿病周围神经病变

目的 观察氢质子磁共振频谱（¹H-MRS）检测腓肠肌代谢物对早期评估大鼠糖尿病（DM）模型周围神经病变的价值。方法 将40只SD雄性大鼠随机分为实验组（n=20）与正常组（n=20）。实验组以高糖高脂饲养+注射链脲菌素法建立DM模型。于造模前和造模后7、14、21天采集2组大鼠右下肢腓肠肌¹H-MRS，获得胆碱复合物（Cho）、肌酸复合物（Cr）、细胞内脂质（IMCL）、Cho/Cr及IMCl/Cr值。正常组大鼠予普通饲料喂养。造模后21天行右下肢坐骨神经电生理及病理检查，测量2组坐骨神经运动神经传导速度（MNCV）及感觉神经传导速度（SNCV）。比较实验组内各时间点代谢物浓度值差异及2组间MNCV和SNCV差异，观察病理结果。结果 实验组内不同时间点Cho、Cr、IMCL、Cho/Cr及IMCL/Cr值差异均有统计学意义（F=6.69、5.41、3.65、3.51、3.10，P均<0.05）；造模后14、21天Cr和Cho值均高于造模前（P均<0.05），造模后7天IMCL值高于造模前（P<0.05）。造模后21天实验组右下肢坐骨神经MNCV和SNCV均低于正常组（t=2.74、4.62，P均<0.01）。相比正常组，实验组神经纤维稀疏松散，排列紊乱，部分髓鞘着色浅且不均匀，轴索变细萎缩。结论 ¹H-MRS可无创定量分析骨骼肌代谢，进而早期评估大鼠DM模型DPN。

Quantitative analysis of gastrocnemius metabolites with 1H-MRS for early evaluation on diabetic peripheral neuropathy in diabetic rat models

Objective To explore the value of quantitative analysis of gastrocnemius metabolites with ¹H-MRS for early evaluation on diabetic peripheral neuropathy in diabetic rat models. Methods Totally 40 male SD rats were randomly divided into experimental group and normal group (each n=20). In experimental group, diabetes models were established by feeding with high sugar and high-fat fed diet and streptozotocin injection. The right gastrocnemius ¹H-MRS of 2 groups were collected before modeling as well as 7 days, 14 days and 21 days after modeling. The concentration values of choline-containing compounds (Cho), creatine compounds (Cr), intra-myocellular lipids (IMCL), Cho/Cr and IMCL/Cr were obtained. The rats in normal group were fed with general diet. Electrophysiological and pathological examinations were performed 21 days after modeling, the motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) of right sciatic nerve were measured. The metabolite concentration values at each time point in experimental group were compared, and MNCV and SNCV were compared between groups. The pathological results of 2 groups were observed. Results There were differences of values of Cho, Cho/Cr, Cr, IMCI, IMCI/Cr in experimental group at different time points (F=6.69, 5.41, 3.65, 3.51, 3.10, all P<0.05). Cho and Cr values 14 days and 21 days after modeling were higher than those before modeling (both P<0.05), and IMCL values 7 days after modeling were higher than those before modeling (P<0.05). MNCV and SNCV of the right sciatic nerve in experimental group were slower than those in normal group 21 days after modeling (t=2.74, 4.62, both P<0.05). Compared with normal group, the nerve fibers in experimental group were sparse, loose and disordered, some myelin sheaths were stained lightly and unevenly and axons became thin and atrophic. Conclusion ¹H-MRS can be used for noninvasive quantitative analysis of skeletal metabolites, so as for early evaluation of DPN in rat diabetic models.