Characterization of age-related dolichol increases in the mouse retina.

We characterized the age-related increases in dolichol levels in the mouse retina using liquid chromatography-mass spectrometry (LC-MS). The four major dolichol species, dolichol-17 (Dol-17), Dol-18, Dol-19, and Dol-20-all increased drastically with age. The largest increase was in Dol-18 levels, which rose by a factor of 100 from postnatal day 5 (PD 5) to PD 600. These increases occurred in two distinct phases: a linear increase in Phase I (PD 5 to PD 30), and a nonlinear increase in Phase II (PD 30 to PD 600). There was also an age-dependent shift in the dolichol chain length profile toward the shorter chain lengths. Dol-19 was the dominant species from PD 5 to PD 15, but Dol-18 became dominant after PD 20. Age-related changes in cholesterol and coenzyme Q9 (CoQ9) were much smaller than those in dolichol but followed the same biphasic pattern. The increase in dolichol levels may influence the physical properties of cell membranes, act as an ultraviolet (UV) filter for retinal cells, and serve as a biomarker of retinal aging.