RECOVERY OF LIPID PROFILE AFTER CUPRIZONE-INDUCED DEMYELINATION IN YOUNG AND MATURE C57BL/6 MICE

Myelin lipid composition undergoes region-specific changes during brain development and maturation. Disruption of these developmental lipid dynamics is associated with impaired nerve conduction and clinical symptoms. However, whether lipid profiles recover equally after toxin-induced demyelination in young versus mature brain tissue remains unclear. This study examined the cortex and commissures of 3- and 6-month-old male C57BL/6 mice (N = 48), randomly assigned to either a cuprizone-treated group (0.2% CPZ for 20 days) or a non-treated control group (CTRL). After a 20-day recovery period, imaging mass spectrometry (IMS) was performed on fresh-frozen brain sections in negative ion mode (m/z 600–1000). Lipids were tentatively identified using the Human Metabolome Database (HMDB) and METASPACE. Structural remyelination was assessed immunohistochemically using antibodies against myelin-associated glycoprotein (MAG) and myelin basic protein (MBP). Partial least squares discriminant analysis (PLS-DA) revealed clear separation between CTRL and CPZ groups, driven by alterations in lipids associated with myelin maturation, including glycosphingolipids, phosphoglycerols, and phosphatidylcholines. In both age groups, post-recovery lipid profiles showed reduced phosphatidylethanolamines and phosphatidic acid. In contrast to older mice, younger mice exhibited persistent depletion of glycosphingolipids, phosphatidylcholines, and phosphoglycerols after recovery. A 20-day recovery period was insufficient to fully restore the physiological lipid profile in either age group. However, in younger mice, glycolipid deficits were accompanied by upregulation of MAG and restoration of myelin structural integrity. In older mice, despite less pronounced lipid changes, recovery of MBP expression and myelin integrity was not observed.