不同含量碳水化合物饮食对大鼠心脏和脑18^F-FDG摄取的影响

Effects of different carbohydrate diets on cardiac and brain uptake of ^(18)F-FDG in Wistar rats

目的探讨不同含量碳水化合物饮食对大鼠心脏和脑组织18F-FDG摄取的影响。方法以标准饮食饲养2周后,保持饮食总能量不变,将15只Wistar大鼠随机分为3组:低碳水化合物组(LC)、中碳水化合物组(IC)和高碳水化合物组(HC);每组大鼠每种饮食饲养4周后,对动物行18F-FDGPET全身显像,于第2天尾静脉取血测定酮体、葡萄糖、胰岛素和胰高血糖素的含量。图像经计算机处理,获取心脏和脑的最大标准摄取值(SUVmax)。结果心脏SUVmax分别为:LC组3.27±0.43,IC组10.92±0.89,HC组10.95±0.81;脑SUVmax:LC组4.78±0.19,IC组4.04±0.15,HC组3.77±0.24。LC组与IC和HC组之间的差异均有统计学意义(P<0.001),IC和HC组间差异无统计学意义。LC组酮体为(726.10±65.95)μmol/L,约为IC和HC组的6～7倍;血清酮体水平与心脏SUVmax呈负相关(r=-0.764,P<0.001),与脑SUVmax呈正相关(r=0.569,P<0.001);各组间血清胰岛素、血糖和胰高血糖素的差异均无统计学意义。结论长期极低碳水化合物饮食使大鼠心脏对FDG的摄取明显降低,而脑组织对葡萄糖的摄取略有增加。

Objective To assess the effects of different carbohydrate diets on cardiac and brain uptake of 18^F-FDG in Wistar rats. Methods After fed with the standard diet and total energy was kept unchanged, 15 Wistar rats were randomly divided into 3 groups （each n= 5）： low carbohydrate （LC）, intermediate carbohydrate （IC） and high carbohydrate （HC）. Each group was fed with every diet for 4 weeks and then underwent MicroPET imaging using 18^F-FDG, respectively. Blood samples from tail vein were collected for the analysis of ketone body, glucose, insulin and glucagon on the next day. SUVmax of heart and brain was obtained with computer processing. Results SUVmax of heart was 3.27±0.43 in LC group, 10. 92±0.89 in IC, and 10.95±0.81 in HC group; SUVmax of brain was 4.78±0. 19 in LC group, 4.04±0.15 in IC group and 3.77±0. 24 in HC group. There was difference between LC and the other two groups （P〈0.01）, whereas no difference was found between IC and HC group. Serum ketone body concentration was （726.10±65.95） μmol/L in LC group, which was 6-7 times higher than that in IC and HC group. Serum ketone body was negatively correlated with cardiac SUVmax （r=-0. 764, P〈0. 001）, while positively correlated with the brain SUVmax. No difference of serum glucose, insulin and glucagon was found between two groups. Conclusion Long term very low carbohydrate diet makes cardiac uptake of FDG decreased and brain uptake increased.