Direct drug delivery to the cochlea is associated with the risk of irreversible damage to the ear. In this study, liposome and polymersome nanoparticles (NPs), both formed from amphiphilic molecules (lipids in liposomes and block copolymers in polymersomes), were tested as potential tools for drug delivery to the cochlea via application onto the round window membrane in adult mice (strain C3H). One day after round window membrane application, both types of NPs labeled with fluorescent markers were identified in the spiral ganglion in all cochlear turns without producing any distinct morphological or functional damage to the inner ear. NPs were detected, although to a lesser extent, in the organ of Corti and the lateral wall. The potential of liposome and polymersome NPs as therapeutic delivery systems into the cochlea via the round window membrane was evaluated using disulfiram, a neurotoxic agent, as a model payload. Disulfiram-loaded NP delivery resulted in a significant decrease in the number of spiral ganglion cells starting 2 days postapplication, with associated pronounced hearing loss reaching 20-35 dB 2 weeks postapplication as assessed through auditory brainstem responses. No changes in hair cell morphology and function (as assessed by recording otoacoustic emissions) were detected after disulfiram-loaded NP application. No effects were observed in controls where solution of free disulfiram was similarly administered. The results demonstrate that liposome and polymersome NPs are capable of carrying a payload into the inner ear that elicits a biological effect, with consequences measurable by a functional readout.

• MeSH
• apoptóza účinky léků   MeSH
• Cortiho orgán účinky léků   ultrastruktura   MeSH
• cytotoxiny aplikace a dávkování   farmakologie   MeSH
• disulfiram aplikace a dávkování   farmakologie   MeSH
• fenestra rotunda účinky léků   metabolismus   ultrastruktura   MeSH
• ganglion spirale cytologie   účinky léků   MeSH
• kaspasa 3 metabolismus   MeSH
• kochlea účinky léků   metabolismus   ultrastruktura   MeSH
• lékové transportní systémy metody   MeSH
• liposomy analýza   MeSH
• myši MeSH
• nanočástice analýza   MeSH
• povrchově aktivní látky chemie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Calbindin (CB) and S100 are calcium-binding proteins expressed in the inner ear in vertebrates. Information about their developmental roles is incomplete. This study investigated the expression patterns of CB and S100 in C3H mice using immunohistochemistry, from embryonic day 11 (E11) to postnatal day 10 (P10). CB was expressed in the otocyst and vestibulocochlear ganglion (VCG) from E11. In the cochlea at E17, CB immunoreactivity clearly labeled the VCG, the outer and inner hair cells, and the stria vascularis. CB staining was also present in the vestibular sensory cells, including their nerve fibers. Two days later, to this expression pattern was added the labeling of Kolliker's organ. Early postnatal CB expression encompassed VCG neurons, auditory hair cells, their afferent nerve fibers, and cells of the cochlear lateral wall. The first signs of S100 immunostaining of cochlear and vestibular epithelial cells appeared at E14. At E17 S100 immunoreactivity was found in a restricted expression pattern in the cochlea. Immunostaining was also present in the sacculus and utriculus and their afferent fibers. The Deiters', pillar and inner hair cells, and the VCG were S100-positive from E19. Postnatally, S100 staining also appeared in the inner hair cells and Deiters' cells, in some VCG neurons, and, in addition, in the spiral limbus, the spiral prominence, and the intermediate cells of the stria vascularis. This study demonstrates that the sites of CB and S100 expression in the mouse inner ear during embryonic and early postnatal development do not overlap and signal independent developmental patterns. (c) 2009 Wiley-Liss, Inc.

• MeSH
• embryo savčí MeSH
• financování organizované MeSH
• imunohistochemie MeSH
• kochlea embryologie   metabolismus   růst a vývoj   MeSH
• myši inbrední C3H MeSH
• myši MeSH
• neurony metabolismus   MeSH
• novorozená zvířata MeSH
• proteiny S100 metabolismus   MeSH
• S100 kalcium vázající protein G MeSH
• stria vascularis metabolismus   MeSH
• těhotenství MeSH
• tkáňová distribuce MeSH
• vláskové buňky metabolismus   MeSH
• vnitřní ucho embryologie   metabolismus   růst a vývoj   MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• zvířata MeSH

The Fischer 344 rat strain has been frequently used as an animal model of rapid aging. The present study was aimed at evaluating the incidence of apoptotic cells in the inner ear of 20-24-month-old F344 rats and to correlate it with cochlear function using otoacoustic emissions. Staining with cresyl violet and the enzymatic labeling (terminal deoxynucleotidyl transferase, TdT) of fragmented DNA revealed large numbers of apoptotic cells in the marginal and basal layers of the stria vascularis and in adjacent cells of the spiral ligament. The amplitudes of distortion products otoacoustic emissions (DPOAEs), which reflect functional state of the outer hair cells, were significantly reduced or totally absent in these animals. In contrast to old F344 rats, no marked DPOAE amplitude reduction and smaller numbers of apoptotic cells were found in young 4-month-old F344 rats or in aged 24-28-month-old Long Evans rats. The accumulation of apoptotic cells, mainly in the basal layer of the stria vascularis and in adjacent cells of the spiral ligament, leads to a detachment of the stria vascularis from the spiral ligament and results in the impairment of outer hair cell function. This specific type of strial deterioration suggests that aged F344 rats can serve as an animal model of strial presbycusis.

• MeSH
• apoptóza MeSH
• buněčná smrt MeSH
• druhová specificita MeSH
• financování organizované MeSH
• fragmentace DNA MeSH
• imunohistochemie MeSH
• kochlea cytologie   fyziologie   růst a vývoj   MeSH
• krysa rodu rattus MeSH
• modely u zvířat MeSH
• potkani inbrední F344 fyziologie   růst a vývoj   MeSH
• sluch fyziologie   MeSH
• stárnutí fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

Hearing function in the Fischer 344 (F344) albino inbred strain of rats deteriorates with aging faster than in other strains, in spite of the small hair cell loss in old F344 animals [Popelar, J., Groh, D., Pelanova, J., Canlon, B., Syka, J., 2005. Age-related changes in cochlear and brainstem auditory function. Neurobiol. Aging, in press.]. This study was aimed at elucidating the structural changes in the inner ear of this rat strain during aging. Cochlear histopathology was examined in 20-24-month-old F344 rats and compared with that of young F344 rats (4 months) and of old rats of the Long-Evans (LE) strain. Hematoxylin/eosin staining in aged F344 rats showed degenerative changes in the organ of Corti, consisting of a damaged layer of marginal cells, reduced vascularization of the stria vascularis and a distorted tectorial membrane detached from the organ of Corti. Age-related changes in collagen distribution were observed with Masson's trichrome staining in the spiral ligament of old F344 rats. The results of immunohistochemical staining for type II collagen revealed a marked decrease in collagen fibers in the area connecting the spiral ligament and stria vascularis and a decrease in area IV fibrocytes in old F344 but not in LE rats. These findings may contribute to an explanation of the substantial hearing loss found in old F344 rats.

• MeSH
• azosloučeniny analýza   MeSH
• barvicí látky analýza   MeSH
• Cortiho orgán chemie   MeSH
• eosin analýza   MeSH
• fluorescenční barviva analýza   MeSH
• hematoxylin analýza   MeSH
• imunohistochemie metody   MeSH
• kochlea * fyziologie   chemie   MeSH
• kolagen typ II analýza   MeSH
• kolagen * analýza   MeSH
• krysa rodu rattus MeSH
• membrana tectoria chemie   MeSH
• methylová zeleň analýza   MeSH
• potkani inbrední F344 MeSH
• stárnutí * fyziologie   MeSH
• stria vascularis chemie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH