Pilatus U, Shim H, Artemov D, Davis D, van Zijl P C, Glickson J D
Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Magn Reson Med. 1997 Jun;37(6):825-32. doi: 10.1002/mrm.1910370605.
Diffusion NMR spectroscopy was used to study intracellular volume and apparent water diffusion constants in different cell lines (DU145, human prostate cancer; AT3, rat prostate cancer; MCF-7, human breast cancer; RIF-1, mouse fibrosacroma). The cells were grown on various matrices (collagen sponge, collagen beads, polystyrene beads) which enabled continuous growth in perfused high density cell culture suitable for NMR studies. In perfused cell systems, the attenuation of the water signal versus the squared gradient strength was fitted by the sum of two decaying exponentials. For the slowly decaying component the apparent water diffusion constant at 37 degrees C was 0.22 (+/-0.02) x 10(-9) s/m2 for all cell lines at diffusion times > 100 ms. It continuously increased up to 0.47 (+/-0.05) x 10(-9) s/m2 when the diffusion time was decreased to 8 ms, indicating restricted diffusion. No significant effect of the matrices was observed. The fractional volume of the slow component as determined from the biexponential diffusion curve correlated with the relative intracellular volume, as obtained from the cell density in the sample and the cell size as measured by light microscopy. Therefore, this simple NMR approach can be used to determine intracellular volume in perfused cell cultures suitable for NMR studies. Using this information in combination with spectroscopic data, changes in intracellular metabolite concentration can be detected even when the cellular volume is changing during the experiment. The apparent diffusion constant for the fast diffusing component varied with growth matrix, cell density and cell type and also showed the typical characteristics of restricted diffusion (increase of apparent diffusion constant with time).
扩散核磁共振波谱法用于研究不同细胞系（DU145，人前列腺癌；AT3，大鼠前列腺癌；MCF - 7，人乳腺癌；RIF - 1，小鼠纤维肉瘤）中的细胞内体积和表观水扩散常数。细胞在各种基质（胶原海绵、胶原珠、聚苯乙烯珠）上生长，这些基质能使细胞在适合核磁共振研究的灌注高密度细胞培养中持续生长。在灌注细胞系统中，水信号强度随梯度强度平方的衰减由两个衰减指数之和拟合。对于缓慢衰减成分，在扩散时间>100 ms时，所有细胞系在37℃下的表观水扩散常数为0.22（±0.02）×10⁻⁹ s/m²。当扩散时间降至8 ms时，该常数持续增加至0.47（±0.05）×10⁻⁹ s/m²，表明存在扩散受限。未观察到基质有显著影响。由双指数扩散曲线确定的慢成分的分数体积与相对细胞内体积相关，相对细胞内体积可通过样品中的细胞密度和光学显微镜测量的细胞大小获得。因此，这种简单的核磁共振方法可用于确定适合核磁共振研究的灌注细胞培养中的细胞内体积。结合光谱数据使用该信息，即使在实验过程中细胞体积发生变化时，也能检测到细胞内代谢物浓度的变化。快速扩散成分的表观扩散常数随生长基质、细胞密度和细胞类型而变化，并且也显示出扩散受限的典型特征（表观扩散常数随时间增加）。
