1181
Effects of Maternal Nutrient Restriction on Muscle Satellite Cell Activity

Wednesday, July 23, 2014
Exhibit Hall AB (Kansas City Convention Center)
Joseline S. Raja , Department of Animal Science, University of Connecticut, Storrs, CT
Maria L. Hoffman , Department of Animal Science, University of Connecticut, Storrs, CT
Kristen N. Peck , Department of Animal Science, University of Connecticut, Storrs, CT
Kristen E. Govoni , Department of Animal Science, University of Connecticut, Storrs, CT
Steven A. Zinn , Department of Animal Science, University of Connecticut, Storrs, CT
Sarah A. Reed , Department of Animal Science, University of Connecticut, Storrs, CT
Abstract Text:

Postnatal muscle growth is altered by poor maternal nutrition during gestation. Satellite cells are myogenic precursor cells that contribute to postnatal muscle growth. Satellite cell activity can be evaluated by the expression of several transcription factors that are critical for proper myogenesis. Pax7 is expressed in quiescent and active satellite cells. Expression of MyoD is increased in active and proliferating satellite cells and terminal differentiation is marked by expression of myogenin. We hypothesized that poor maternal nutrition during gestation would alter the temporal expression of Pax7, MyoD and myogenin in satellite cells in vitro. Multiparous ewes (n = 23) were housed individually and fed 100% or 60% NRC requirements beginning at d 31 ± 1.3 of gestation. Lambs from control-fed (CON) or restricted-fed (RES) ewes were euthanized within 24 h of birth (d 1; n = 12) or were maintained on a control diet until 3 mo of age (n = 11). Satellite cells were isolated from the semitendinosus muscle at necropsy and cryopreserved until further use. Satellite cells were cultured in growth media for 24, 48 or 72 h before immunostaining for Pax7, MyoD and myogenin. Hoescht dye was used to visualize nuclei. The percent of immunopositive cells was calculated as the number of immunopositive cells divided by total nuclei. Data were analyzed by PROC MIXED procedure of SAS. After 24 h of culture, the percent of cells expressing MyoD was 5-fold greater in RES lambs at birth (58.40 ± 12.08%) than cells of CON lambs (11.68 ± 17.08%; P = 0.03). After 48 h of culture, there was a greater percentage of cells expressing myogenin in RES lambs at birth (63.25 ± 14.00%) compared with cells from CON lambs (17.57 ± 17.08%; P = 0.04). However, after 72 h of culture the percent of satellite cells expressing myogenin in RES lambs at birth (40.07 ± 14.00%) was approximately 50% less than cells from CON lambs (83.98 ± 17.08%; P = 0.05). There were no differences in the percent of Pax7 immunopostive cells at birth, or any factors in cells from lambs at 3 mo of age (P > 0.05). In conclusion, restricted nutrient availability during gestation alters the temporal expression of myogenic regulatory factors in the offspring and is suggestive of precocious differentiation.

Keywords: muscle, satellite cells, poor maternal nutrition

See more of: Growth & Development Poster II
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