hearing/vestibular/ear
• although relatively normal at P14 and only mildly affected by P17-21, cochlear hair cells display a base-to-apex degeneration by P31, which is more severe in the basal turn and milder in the middle and apical turns
• cochlear hair cell degeneration precedes loss of spiral ganglion neurons
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• by P31, homozygotes display a progressive degeneration in the organ of Corti which is prominent at later times (P120)
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• at P14, the stria vascularis is nearly doubled in thickness
• as early as 2 weeks, marginal and basal epithelial barrier layers display aberrant cortical actin patterns
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• at P14, blood vessels within the stria vascularis appear dilated
• at P30, strial blood vessels are highly dilated and tortuous, possibly due to an unusually high pressure load
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• as early as ~2 weeks of age, homozygotes exhibit disorganization of strial basal cell barriers
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• from P31 to 6 months, the stria vascularis displays progressive hyperpigmentation, an indicator of damage and altered function of intermediate cells
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• as early as ~2 weeks of age, homozygotes exhibit disorganization of strial marginal cell barriers, with both multinuclear and anuclear marginal cells of heterogeneous sizes
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• bilateral absence of normal with the presence of few enlarged utricular otoconia indicates perturbed ionic composition of the vestibular labyrinth fluids
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• at P7, utricular otoconia are largely absent in both ears
• in contrast, saccular otoconia remain normal
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• at P7, the few utricular otoconia remaining in mutant ears are enlarged
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• at one month of age, homozygotes totally lack characteristic ABR waveforms at intensities of 100 db of SPL in response to all test stimuli (click, 8, 16, and 32 kHz)
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• at 1 and 3 months of age, homozygotes display no measurable DPOAEs
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nervous system
• although relatively normal at P14 and only mildly affected by P17-21, cochlear hair cells display a base-to-apex degeneration by P31, which is more severe in the basal turn and milder in the middle and apical turns
• cochlear hair cell degeneration precedes loss of spiral ganglion neurons
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• spiral ganglion neurons are present up to P21 but have largely disappeared by 4 months
• at 6 months, a striking bilateral absence of spiral ganglion neurons is observed
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cardiovascular system
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• homozygotes show no evidence of embryonic lethality or hemorrhaging; no other analysis done in J:106055
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• at P14, blood vessels within the stria vascularis appear dilated
• at P30, strial blood vessels are highly dilated and tortuous, possibly due to an unusually high pressure load
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pigmentation
• from P31 to 6 months, the stria vascularis displays progressive hyperpigmentation, an indicator of damage and altered function of intermediate cells
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behavior/neurological
• homozygotes display a head tilt much less frequently relative to mice doubly homozygous for Edg3tm1Rlp and Edg5tm1Rlp
• notably, adult homozygotes exhibit normal balance and motor function when tested on a rotarod by balance beam walking or in a swimming test
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hematopoietic system
• in the spleen and mesenteric lymph nodes
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• B cells exhibit growth advantage in chronic germinal centers of wild-type mice
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• after 1 year
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• in the mesenteric lymph nodes after 1 year
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• after 1 year
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• the boundary between the germinal center and the mantle zone is often less well defined compared to in wild-type mice
• however, the segregation is largely revered in Sphk1-deficient hosts
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immune system
• in the spleen and mesenteric lymph nodes
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• B cells exhibit growth advantage in chronic germinal centers of wild-type mice
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• after 1 year
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• in the mesenteric lymph nodes after 1 year
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• after 1 year
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• the boundary between the germinal center and the mantle zone is often less well defined compared to in wild-type mice
• however, the segregation is largely revered in Sphk1-deficient hosts
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cellular
• in the spleen and mesenteric lymph nodes
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• B cells exhibit growth advantage in chronic germinal centers of wild-type mice
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