MONITORING OF CELL-VOLUME AND WATER EXCHANGE TIME IN PERFUSED CELLS BY DIFFUSION-WEIGHTED H-1-NMR SPECTROSCOPY

Diffusion of intracellular water was measured in perfused cells embedd ed in basement membrane gel threads. F98 glioma cells, primary astrocy tes, and epithelial KB cells were used and were exposed to osmotic str ess, immunosuppressiva, the water channel blocker p-chloromercuriobenz enesulfonate (pCMBS), and apoptotic conditions. With diffusion-weighte d H-1 NMR spectroscopy changes in the intracellular signal could be mo nitored and quantified with single signal (ss), constant diffusion tim e (ct), and constant gradient strength (eg) experiments. The temporal resolution of the ss monitoring was 3.5 s with a standard deviation of 0.5% of the signal intensity and 32 s (3%) with ct monitoring, respec tively. A mean intracellular residence time of water was determined wi th the cg experiment to about 50 ms. Changes of this exchange time fro m (51.9 +/- 1.0) to (59.0 +/- 1.1) ms were observed during treatment w ith pCMBS. The changes in the diffusion attenuated signal could be sim ulated analytically varying the intracellular volume fraction and exch ange time by combination of restricted diffusion (Tanner model) and wa ter exchange (Karger model). This sensitive and noninvasive NMR method on perfused cells allows to determine changes in the intracellular vo lume and residence time in a simple and accurate manner. Many further applications as anoxia, volume regulation, ischemia and treatment with various pharmaceuticals are conceiveable to follow up their effect on the cell volume and the exchange time of intracellular water. (C) 199 8 John Wiley & Sons, Ltd.