Analysis Tools
reproductive system
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• female mice exhibit normal fertility
• adult males show normal testes weight, testis histology, paired seminal vesicle weight, sperm morphology and sperm concentration
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• all males mated with fertile wild-type females fail to produce offspring
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• mutant sperm fail to fertilize oocytes in vivo and in vitro
• during IVF assays, many mutant sperm remain associated with either the zona pellucida of intact oocytes or the cell membrane of zonafree oocytes/zygotes
• mutant sperm bind to the zona pellucida surrounding 2cell embryos formed by IVF with wildtype sperm, indicating failure to react to normal zona modifications that prevent polyspermy
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• after IVF by mutant sperm, less than 5% of untreated or glutathione (GSH)-treated zona-intact oocytes develop to the 2cell stage and no blastocyst embryos are observed by 96 hr postfertilization, unlike in wild-type sperm controls where >90% of zona-intact oocytes develop to the 2cell stage and ~90% of 2cell embryos in untreated and GSHtreated IVF develop to the blastocyst stage
• however, 89% of zonafree oocytes fertilized by mutant sperm develop to the 2cell stage, a frequency that is similar to or higher than in wild-type sperm controls (83%), and 78% of 2cell embryos develop to the blastocyst stage, a rate that is also similar to the wild-type group (73%)
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• mutant sperm fail to penetrate the oocytes zona pellucida during IVF
• however, mutant sperm are competent to fertilize zonafree oocytes
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• mutant epididymal sperm rapidly form multiple clumps during incubation in IVF medium, a behavior rarely seen among wildtype sperm
• sperm clumps swim as a cluster in IVF medium; however, motility is sustained over several hours and single sperm can be released from the clumps by mechanical disruption
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• individual sperm analysis by CASA showed a significantly lower % of progressively motile sperm than in wild-type controls
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• individual sperm analysis by CASA immediately upon release from the epididymis (before clumping is observed) showed a significantly lower % of motile sperm than in wild-type controls
• average path velocity (VAP), straight line velocity (VSL) and curvilinear velocity (VCL) are all significantly reduced
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• mutant sperm undergo a higher rate of spontaneous acrosome reaction than wild-type sperm
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cellular
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• individual sperm analysis by CASA showed a significantly lower % of progressively motile sperm than in wild-type controls
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• individual sperm analysis by CASA immediately upon release from the epididymis (before clumping is observed) showed a significantly lower % of motile sperm than in wild-type controls
• average path velocity (VAP), straight line velocity (VSL) and curvilinear velocity (VCL) are all significantly reduced
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