title: Osmotic and aging effects in caviar oocytes throughout water and lipid changes assessed by 1H NMR T1 and T2 relaxation and MRI.
abstract: By combining NMR relaxation spectroscopy and magnetic resonance imaging techniques, unsalted (us) and salted (s) caviar (Acipenser transmontanus) oocytes were characterized over a storage period of up to 90 days. The aging and the salting effects on the two major cell constituents, water and lipids, were separately assessed. T1 and T2 decays were interpreted by assuming a two-site exchange model. At Day 0, two water compartments that were not in fast exchange were identified by the T1 relaxation measurements on the us oocytes. In the s samples, T1 decay was monoexponential. During the time of storage, an increment of the free water amount was found for the us oocytes, ascribed to an increased metabolism. T1 and T2 of the s oocytes shortened as a consequence of the osmotic stress produced by salting. Selective images showed the presence of water endowed with different regional mobility that severely changed during the storage. Lipid T1 relaxation decays collected on us and s samples were found to be biexponential, and the T1 values lengthened during storage. In us and s oocytes, the increased lipid mobility with the storage was ascribed to lipolysis. Selective images of us samples showed lipids that were confined to the cytoplasm for up to 60 days of storage.
authors.affiliation: Università degli Studi di Milano, Dipartimento di Scienze e Tecnologie Biomediche, Segrate (MI), I-20090 Italy. maristella.gussoni@unimi.it
authors.forename: Maristella
authors.initials: M
authors.lastname: Gussoni
authors.forename: Fulvia
authors.initials: F
authors.lastname: Greco
authors.forename: Alessandra
authors.initials: A
authors.lastname: Vezzoli
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Paleari
authors.forename: Vittorio Maria
authors.initials: VM
authors.lastname: Moretti
authors.forename: Barbara
authors.initials: B
authors.lastname: Lanza
authors.forename: Lucia
authors.initials: L
authors.lastname: Zetta
mesh_terms: D000818:Animals; D016922:Cellular Senescence; D005260:Female; D005399:Fishes / Q000033:anatomy & histology* / Q000378:metabolism*; D066298:In Vitro Techniques; D050356:Lipid Metabolism; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism*; D009997:Osmotic Pressure; D012965:Sodium Chloride; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D012965:Sodium Chloride