Abstract
There are increased risks for deglutition disorders in people with Down syndrome (DS). Although mouse models have been used to study the biological underpinnings of DS in other areas, relatively little is known about swallowing phenotypes in these models. We hypothesized that swallowing performance would be affected in adult mouse models of DS, relative to typical control mice. Videofluoroscopic swallow studies (VFSS) were conducted on adults of two mouse models of DS: Ts65Dn and Dp(16)1Yey, and evaluated in comparison with age-matched controls. Relative to other groups, adult Ts65Dn showed significantly slower swallow rates, longer inter-swallow intervals (ISI), and greater numbers of jaw excursion cycles preceding each swallow. In contrast, adult Dp(16)1Yey mice showed swallowing performance similar to control mice. Exploratory quantitative analyses of the intrinsic tongue (transverse muscle), and extrinsic tongue muscles [genioglossus (GG), styloglossus (SG), and hyoglossus (HG)] showed no significant differences between genotype groups in myosin heavy chain isoform profiles. Collectively, these findings suggest that while swallowing is typical in adult Dp(16)1Yey, swallowing in adult Ts65Dn is atypical due to unknown causes. The finding that adult Ts65Dn may have utility as a model of dysphagia provides new opportunities to elucidate biological underpinnings of dysphagia associated with DS.
Highlights
Down syndrome (DS), typically caused by a trisomy of the 21st chromosome, is associated with increased risks for feeding challenges and deglutition disorders across the lifespan (Lazenby, 2008)
These analyses indicate normal jaw cycle speeds in the Ts65Dn group, but a greater number of jaw cycles preceding each swallow (JSR), associated with increases in the amount of time elapsed between swallows (ISI)
Ts65Dn showed significant increases in the JSR, which is the number of jaw cycles preceding each swallow
Summary
Down syndrome (DS), typically caused by a trisomy of the 21st chromosome, is associated with increased risks for feeding challenges and deglutition disorders across the lifespan (Lazenby, 2008). These can coincide with medical comorbidities (Dinan and Golden, 1990; Zárate et al, 2001; Prasher et al, 2004; Abanto et al, 2011), craniofacial differences (Hashimoto et al, 2014), sensory differences (Frazier and Friedman, 1996), and behavioral differences (Homer and Carbajal, 2015). One avenue for addressing this research challenge may be the use of animal models, which offer opportunities to explore aspects of pathophysiology of feeding and swallowing that cannot be studied in patient populations (German et al, 2017)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call