Gaurav Singhal, Jayde C Sitko, Erin H Fisher, Miranda Cullins, Nadine P Connor, Tiffany J Glass
Soft diets did not worsen genotype specific differences in VFSS measures. Predictor level BDNF findings were exploratory because the corresponding overall models were not statistically significant.
BACKGROUND: Children with Down syndrome (DS) often show feeding and swallowing difficulties, including prolonged reliance on soft diets. The Ts65Dn mouse model mirrors oromotor challenges in DS, yet the impacts of extended postweaning periods of soft food conditions are not well understood. We examined whether a soft food condition from postnatal day (P)21-P34 alters oral motor behaviors, weight, swallow function, and hypoglossal nucleus BDNF expression in Ts65Dn vs. euploid controls, hypothesizing that soft food would impact these outcomes.
METHODS: Male and female Ts65Dn and euploid littermates were assigned to hard or soft food (HF, SF) from P21-P34. Daily body weight and water intake were recorded. Videofluoroscopic swallow studies (VFSS) measured swallow rate, inter-swallow interval (ISI), jaw excursion rate (JER), and jaw cycle swallow ratio. ProBDNF and mature BDNF were quantified in hypoglossal nucleus at P35. Water consumption was analyzed at the cage level, and BDNF outcomes were analyzed using generalized linear models. Data were analyzed using mixed effects and three-way ANOVA with Sidak post hoc correction (α = 0.05).
RESULTS: Ts65Dn weighed significantly less than euploid control at P21 and P34. Mice in all genotype groups licked significantly more water in the HF condition than in the SF condition. VFSS revealed a significant genotype effect on ISI, with higher ISI in Ts65Dn than euploid mice. A sex x food texture x genotype interaction was detected for JER, with female Ts65Dn HF mice showing lower JER than female euploid HF mice. None of the overall models for proBDNF, mature BDNF, or the mature BDNF/proBDNF ratio reached statistical significance, although predictor level associations were observed for sex with proBDNF and food condition with mature BDNF.
CONCLUSIONS: Soft diets did not worsen genotype specific differences in VFSS measures. Predictor level BDNF findings were exploratory because the corresponding overall models were not statistically significant.