Growth and survival characteristics of mice.

Characterization of growth and survival of mice displaying early onset hypertonic symptoms is critical as these animals are important for research investigating mechanisms and treatments of pediatric conditions associated with hypertonia, such as cerebral palsy. Currently, most animal models of cerebral palsy reproduce risk factors for developing this condition, with most failing to develop the physical symptoms or failing to survive in the postnatal period. The B6.Cg- /J (Gly receptor mutation) transgenic mouse ( mouse), displays symptoms of early onset hypertonia, though little has been reported on growth and survival, with no reports of growth and survival since genotyping became available. We found that the majority of mice display symptoms by P14-P16. Of mice surviving to weaning, only ~9% were mice. By weaning age, mice had significantly lower weights than their heterozygote and wild-type littermates. Of mice that died after weaning and prior to use in experiments or being culled, 48% were mice. The poor growth and decreased survival of mice across multiple developmental and adult ages resembled the varied survival rates observed in humans with mild or severe cerebral palsy. The understanding of the expected survival of these mice is helpful for planning breeding and animal numbers for experiments. Due to the symptoms and timing of symptom onset, mice will be valuable in uncovering mechanisms and long-term effects of early onset hypertonia in order to move toward interventions for these conditions.