The present proposal is a collaborative study designed to determine precise correlations between data obtained from non-invasive nuclear magnetic resonance (NMR) spectroscopy, and those obtained from invasive morphological - physiological studies on human and rabbit lenses in diabetes. The primary objective is to identify the most effective NMR measurements for long term monitoring of the functional integrity of the lens in vitro and, ultimately, in vivo our goal is to establish a non-invasive technique for detecting pre-cataractous lenticular alterations. We will use a multinuclear NMR approach (H-1,C-13, K-39,N-23,P-31), to obtain data representative of lenticular biochemistry. To accomplish this lenses will be subjected to 3 well-established diabetic, physiological stress factors: 1) osmotic stress; 2) oscillating glucose levels; and 3) changes in aqueous humor pH. The cataractogenic potency of each will be studied singly and in combination. We will emphasize human lens studies. Because of the differences between human lenses, due to a variety of factors, parallel studies on a well-controlled animal model will be conducted. Our approach is to determine effects of these physiological stress factors on the lens under precisely defined conditions, which are attainable by the use of an organ culture perfusion system. The intended invasive techniques for definition of lens alterations are those involved in 1) morphological studies by light and electron microscopy (SEM and TEM); 2) visualization and measurement of extracellular space; 3) analysis of Na+, K+ and Ca++ by atomic absorption spectroscopy; 4) lens potential measurements, and 5) documentation of lens clarity by CCRG photography and light scattering. Data obtained from these sources will define 1) the series of events occurring and leading up to opacification, and 2) the point at which these alterations become irreversible. The data can then be precisely correlated with lenticular biochemistry as defined by NMR. Once these correlations are achieved, the biochemical status of a lens, as defined by non-invasive NMR spectroscopy, can be used as an index of the lens functional integrity! Additionally, we expect that our proposed investigations will provide information for scheduling the administration of drugs such as aldose reductase inhibitors, as well as furnish a method for monitoring the lens and, thus, the efficacy of the treatment(s).
