Localization of Glucose and Sorbitol in Incubated Bovine Lenses Using Chemical Shift Imaging

Abstract

To use chemical shift imaging (CSI) to measure the metabolic changes in glucose metabolites in bovine lenses incubated in tissue culture medium 199(TCM 199) with a high concentration of glucose and to evaluate the viability of this method. We detected an accumulation of 13C-labeled glucose and sorbitol in the bovine lenses incubated in TCM 199 containing 50 mM glucose-1-13C for 1, 2, 4, or 6 days using a 2 T CSI Omega system. 1H-13C gradient-selected heteronuclear multiple-quantum coherence (GH-HMQC) in nuclear magnetic resonance (NMR), an indirect method of detecting nuclei in low sensitivity by 1H NMR, was used to observe 13C-enriched metabolites in the bovine lens in vivo. We found an accumulation of 13C-labeled glucose and sorbitol using the 2 T CSI Omega system. The level of glucose increased rapidly in the posterior segment of the lens as well as the anterior segment at one day after the beginning of incubation. Then it diminished gradually, and could no longer be detected on the 6th day after the start of incubation possibly because of the breakdown of the cell membrane. The levels of sorbitol increased in the anterior area and the equator of the lens one day after the beginning of incubation, and remained unchanged for 6 days. We encountered many problems especially with the imaging resolution (consequently the time for measurement was prolonged), but this approach may be useful for non-invasive monitoring of 13C-labeled compounds. We believe this method will be especially useful for detecting various metabolites in vivo.