Premium
The effect of repair on contractile properties of single permeabilized muscle fibers from congenitally‐clefted goat palates
Author(s) -
Hanes Michael C,
Weinzweig Jeffrey,
Buchman Steven R,
Panter Kip,
Faulkner John A,
Yu Deborah,
Cederna Paul S,
Larkin Lisa M
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a805-c
Subject(s) - muscle fibre , anatomy , chemistry , biology , skeletal muscle
We hypothesize that differences in levator veli palatini (LVP) muscle characteristics prior to surgery play a critical role in the prevalence of velopharyngeal insufficiency (VPI) after cleft palate repair. Physiologic differences in single muscle fibers from LVP muscles of congenitally‐clefted (CP) and normal palates (NP) exist: CP consist of predominately type II fibers and have increased fatigability that may result in VPI. We compared contractile properties of 5 single permeabilized muscle fibers from each of three 2 mo old CP goats prior to and 6 mo post cleft palate repair (RP) and one 2 mo NP goat. The cross‐sectional area (CSA), maximum isometric force (F 0 ), and rate of force development (k tr ) were measured, and specific force (sF 0 ) and normalized power (nP max ) were calculated for CP (n=15), RP (n=15), and NP (n=5) fibers. Using k tr to determine the fiber type composition, NP was 100% type I compared to 100% type II in CP. Two of the three RP shifted to 100% type I fibers, while one RP remained 100% type II fibers. The difference in fiber type was the only factor contributing to the increases in CSA, F o , and nP max between the groups. There was no difference in sF 0 between the groups or fiber types. These data show that in 30% of the RP, surgical repair did not result in a shift to type I fibers. This persistent state of type II fibers will lead to increased fatigue in the LVP of these subjects and may lead to VPI. Grants: P30 AG 13283.