Analysis Tools
mortality/aging
|
• a few homozygous mice (6.7%) die around 1 month of age, most (81%) live up to 6 months of age; however, all die by 10 months of age and most death occurs between 7 and 10 months of age
|
behavior/neurological
|
• by 50 days of age mutant mice display clasping and spastic movements in their hind limbs when suspended by the tail
|
|
• mutant mice exhibit a clumsy hopping gait starting at 3 months of age
|
|
• apparent in surviving mutant mice at 8 months of age
|
|
• develops in mutant mice between 4 and 6 months of age
|
nervous system
|
• beginning at 2 months of age and progressing such that 1% of triangularis sterni muscle end-plates are denervated at 2 months of age, 2% at 3 months of age, and 28% at 5 months of age, and a similar progressive denervation is found in extensor digitorum longus muscles which have 57% of end-plates denervated by 5 months of age
• electron microscopy reveals degenerating nerve terminals wrapped by Schwann cells whose processes invade into the synaptic cleft
|
|
• presynaptic terminals appear to retract from their corresponding end-plates beginning by 2 months of age and electron microscopy reveals a marked reduction of synaptic vesicles in the presynaptic nerve terminals with an excessive number of branched tubulovesicular profiles and multilamellar bodies
|
|
• neuron degeneration appears to progress in a distal-to-proximal direction since the ventral roots are normal at 8 months of age, but the myelinated axons in their distal nerves show loss of myelinated axons by 3.5 months of age and this is more severe at 8 months of age
|
|
• electrophysiologic analyses of the extensor digitorum longus shows that the end-plate potential amplitudes are significantly reduced at 3 and 5 months of age, but not significantly abnormal at 1.5 or 2 months of age, that the mean quantal content is significantly reduced at 3 and 5 months of age, and that the latencies are significantly prolonged and the rising slopes significantly decreased at 2, 3, and 5 months of age
|
|
• electrophysiologic analyses of the extensor digitorum longus shows that, although the mEPP amplitide is unaffected, by 2 months of age, and also at 3 and 5 months of age, mEEP frequencies are significantly reduced, indicative of a presynaptic defect resulting in impaired spontaneous synaptic transmission through the neuromuscular junction
|
|
• the decreased end-plate potential and quantal content along with normal acetylcholine receptor staining indicate diminshed neurotransmitter release at the neuromuscular junction
|
|
• at two months of age paired-pulse depression is found in neuromuscular junctions rather than normal paired-pulse facilitation and the rate of end-plate potential rundown increases with age and amplitude
|
skeleton
growth/size/body
 |
• females are significantly smaller than wild-type controls at 12 weeks of age
|
|
|
• females show a significant decrease in body weight at 12 weeks of age
|
reproductive system
|
|
• after superovulation with PMSG plus hCG, oocyte maturation rate (number of mature MII oocytes/total number of oocytes retrieved 100%) is significantly lower than in wild-type controls at 12 weeks of age (65.8% vs 86.5%, respectively)
• a higher rate of abnormal oocytes with cytoplasmic fragmentation is observed, indicating poor oocyte quality
|
|
|
• after superovulation, the number of retrieved oocytes is significantly reduced at 8 and at 12 weeks, but not at 4 weeks of age
|
|
|
• ovaries from 12-week-old females show a significant decrease in protein expression of GJA4 (gap junction protein, alpha 4, aka CX37), suggesting impaired gap junction intercellular communications
|
|
|
• IHC staining of GJA4 shows a noticeable decrease in gap junctions between oocyte and granulosa cells in growing follicles
|
|
|
• antral follicle number is significantly reduced at 12 weeks of age
|
|
|
• females show fewer primordial and pre-antral follicles and a significantly lower number of antral follicles at 12 weeks of age
• in vitro, secondary follicles cultured in the presence of FSH show a markedly smaller follicle diameter starting from day 4; follicles largely stagnate in the preantral stage with only few developing to the preovulation stage on day 6, indicating impaired preantral follicle development with poor response to FSH
• however, no significant difference is found during culture in the absence of FSH
|
small ovary
(
J:361266
)
|
|
• ovaries are significantly smaller at 12 weeks of age
• however, ovarian index % (ovarian weight/body weight) is not significantly altered
|
|
• ovarian tissues from 12-week-old females show a significant decrease in Star (steroidogenic acute regulatory protein) mRNA and protein levels as well as a reduction in ESR1 [estrogen receptor 1 (alpha)] protein level, indicating downregulation of steroid biosynthesis in granulosa cells
• overall decline in ovarian function is similar to the clinical symptoms of diminished ovarian reserve
|
|
|
• females spend significantly more time in the secretory, luteal phase of diestrus
|
|
|
• adult female mice are infertile as a result of impaired early embryo development
|
endocrine/exocrine glands
|
|
• ovaries from 12-week-old females show a significant decrease in protein expression of GJA4 (gap junction protein, alpha 4, aka CX37), suggesting impaired gap junction intercellular communications
|
|
|
• IHC staining of GJA4 shows a noticeable decrease in gap junctions between oocyte and granulosa cells in growing follicles
|
|
|
• antral follicle number is significantly reduced at 12 weeks of age
|
|
|
• females show fewer primordial and pre-antral follicles and a significantly lower number of antral follicles at 12 weeks of age
• in vitro, secondary follicles cultured in the presence of FSH show a markedly smaller follicle diameter starting from day 4; follicles largely stagnate in the preantral stage with only few developing to the preovulation stage on day 6, indicating impaired preantral follicle development with poor response to FSH
• however, no significant difference is found during culture in the absence of FSH
|
small ovary
(
J:361266
)
|
|
• ovaries are significantly smaller at 12 weeks of age
• however, ovarian index % (ovarian weight/body weight) is not significantly altered
|
|
• ovarian tissues from 12-week-old females show a significant decrease in Star (steroidogenic acute regulatory protein) mRNA and protein levels as well as a reduction in ESR1 [estrogen receptor 1 (alpha)] protein level, indicating downregulation of steroid biosynthesis in granulosa cells
• overall decline in ovarian function is similar to the clinical symptoms of diminished ovarian reserve
|
homeostasis/metabolism
|
|
• at 12 weeks of age, serum estradiol (E2) levels are significantly reduced during the follicular phase of proestrus
• however, serum progesterone (P), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels are not significantly altered
|
cellular
|
|
• after superovulation with PMSG plus hCG, oocyte maturation rate (number of mature MII oocytes/total number of oocytes retrieved 100%) is significantly lower than in wild-type controls at 12 weeks of age (65.8% vs 86.5%, respectively)
• a higher rate of abnormal oocytes with cytoplasmic fragmentation is observed, indicating poor oocyte quality
|
|
|
• after superovulation, the number of retrieved oocytes is significantly reduced at 8 and at 12 weeks, but not at 4 weeks of age
|
|
|
• germinal vesicle (GV) oocytes from 12-week-old females exhibit a significantly reduced mitochondrial membrane potential, as determined by the JC-1 (red/green) fluorescence intensity ratio
|
|
|
• when superovulated females are naturally mated with wild-type males, the rate of blastocyst formation is 0% vs 65.52% for wild-type controls, indicating impaired early embryo development
|
