Biological Analysis of a New Spontaneous Mutant Mouse Showing Deafness and Circling Behavior / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Deafness is the most common sensory deficit and hereditary defect in human populations. The present study investigated the causative gene in circling mice using the complementation test. In addition, the phenotypes and histopathologic findings in circler mice, spinner mice, and compound heterozygote mice were analyzed to elucidate the mechanism of causative gene in inner ear deafness. MATERIALS AND METHOD: In order to analyze inner ear pathology in time sequence for the circler mice, spinner mice, and compound heterozygote, five groups of the homozygous mutants of different ages were used: 10, 18, 21, 35, and 90 days old. The organs of Corti and spiral ganglion neurons in the basal and middle turns were included for quantification. For the preparation of genomic DNA, tail tissues were used. RESULTS: The hair cells in the organ of Corti degenerated in a time-dependent manner. In the basal and middle turns, the volume ratio of spiral ganglion neurons significantly decreased as the mutant aged. RT-PCR analysis indicated that transmembrane inner ear (Tmie) was absent in the case of circler mice, similar to spinner mouse of which is defective Tmie gene. Therefore the variations may be a result from strain-specific allelic differences of the Chr 9 Tmie gene itself (allelic heterogeneity). CONCLUSION: The cir mutant is a suitable mouse model for neuroepithelial defects. PCR and RT-PCR analyses suggest that the Tmie transcript is absent in circler mice. This model represents another candidate for human genetic hearing loss.

Cryopreservation of Testicular Spermatozoa using Mouse Zona Pellucida in Intracytoplasmic Sperm Injection Program / 대한불임학회지

The survival rate and motility recovered after cryopreservation of testicular spermatozoa in testicular sperm extraction (TESE)-ICSl program is low. The purpose of this study was to assess the availability and efficiency of mouse empty zona pellucida in cryopreserving human TESE spermatozoa. Mouse empty zonae pellucidae were obtained by extraction of cytoplasm with or without cytochalasin B treatment. Motile sperm from proven-fertile donor and two azoospermic patients after TESE were individually inserted into empty zona pellucida and cryopreserved. Two to five days after cyropreservation, the frozen sperm were thawed and the rates of recovery and motility were observed. The ooplasmic extraction rates of control (N=80) and cytochalasin B treated oocytes (N=80) were 94.0% and 96.2%, respectively (p>0.05). The post-thaw recovery rates of spermatozoa and rates of motility recovery of ejaculate (N=70) and testicular (N=70) sperm were 97.1%, 97.1% and 95.7%, 94.3%, respectively (p>0.05). The results of this study showed that the mouse zone pellucida is useful for cryostorage of single testicular spermatozoa.