Functional characterization of extrinsic tongue muscles in the Pink1-/- rat model of Parkinson disease

• DOI: 10.1371/journal.pone.0240366
• Publication Date: 2020-10-16T17:22:35Z
• Authors: Tiffany J. Glass; Cynthia A. Kelm-N...; John C. Szot; Jacob M. Lake; Nadine P. Connor; Michelle R. Ciucci
• Keywords: PINK1; Hypoglossal nerve; Neuromuscular disease; Pharyngeal muscles; Genioglossus

Parkinson disease (PD) is associated with speech and swallowing difficulties likely due to pathology in widespread brain nervous system regions. In post-mortem studies of PD, has been reported pharyngeal laryngeal nerves muscles. However, it unknown whether PD neuromuscular changes the tongue. Prior work a rat model (Pink1-/-) showed oromotor deficits premanifest stage which suggested sensorimotor impairments these functions. The present study tested hypothesis that Pink1-/- rats show altered tongue function coinciding differences within muscles compared wildtype (WT). Male WT underwent behavioral assays at 4 6 months age (n = 7–8 per group), are time points early disease. At months, genioglossus (GG) styloglossus (SG) were analyzed for myosin heavy chain isoforms (MyHC), α-synuclein levels, myofiber size, centrally nucleated myofibers, junction (NMJ) innervation. greater press force variability, forces rates as WT. Additionally, relative increases MyHC 2a SG, but typical profiles GG. Western blots revealed had more protein than GG, not SG. There no between centrally-nucleated or NMJ was observed nerves, NMJ, vessels both genotypes. Findings stages suggest small several peripheral biological measures, intact motor innervation Future should evaluate measures later determine when robust pathological change contributes functional change, what CNS cause changes. Understanding how affects central mechanisms will help therapy targets disorders.