Rates of myogenesis and myofiber numbers are reduced in late gestation IUGR fetal sheep.

ABSTRACT: Intrauterine growth-restricted (IUGR) fetuses are born with reduced skeletal muscle mass. We hypothesized that reduced rates of myogenesis would contribute to fewer and smaller myofibers in IUGR fetal hindlimb muscle compared to the normally growing fetus. We tested this hypothesis in IUGR fetal sheep with progressive placental insufficiency produced by exposing pregnant ewes to elevated ambient temperatures from 38 to 116 days gestation (dGA; term?=?147 dGA). Surgically catheterized control (CON, n?=?8) and IUGR (n?=?13) fetal sheep were injected with intravenous 5-bromo-2?-deoxyuridine (BrdU) prior to muscle collection (134 dGA). Rates of myogenesis, defined as the combined processes of myoblast proliferation, differentiation, and fusion into myofibers, were determined in biceps femoris (BF), tibialis anterior (TA), and flexor digitorum superficialis (FDS) muscles. Total myofiber number was determined for the entire cross-section of the FDS muscle. In IUGR fetuses, the number of BrdU+ myonuclei per myofiber cross-section was lower in BF, TA, and FDS (P?

SUBMITTER: Chang EI 

PROVIDER: S-EPMC7192794 | biostudies-literature | 2019 Dec

REPOSITORIES: biostudies-literature