TY - JOUR
T1 - Interactive effects of denervation and malnutrition on diaphragm structure and function
AU - Lewis, Michael I.
AU - Lorusso, Thomas J.
AU - Zhan, Wen Zhi
AU - Sieck, Gary C.
PY - 1996/11
Y1 - 1996/11
N2 - The purpose of this study was to examine the interactive effects of unilateral denervation (DN) and prolonged malnutrition (MN) on the structure and function of the diaphragm muscle (Dia). Four groups of rats were studied: control (Con), MN, DN, and DN-MN. MN began 2 wk after DN and lasted 4 wk. In both the DN and DN-MN groups, the relative loss in Dia weight exceeded the relative change in body weight. Compared with the Con group, Dia specific force was reduced by ~40% in both the DN and DN-MN groups but was unaffected in the MN group. Dia fatigue resistance improved in all experimental groups but to a greater extent in the DN and DN-MN groups. In both the DN and DN-MN groups, ~50% of Dia fibers were classified as type IIc, whereas fiber type proportions did not change in the MN group. In the DN group, only type IIb/x fibers atrophied, whereas all fiber types atrophied in the MN and DN-MN groups. We conclude that in the DN-MN group the reduction in specific force combined with the reduction in total cross-sectional area of the muscle significantly curtails Dia force-generating capacity.
AB - The purpose of this study was to examine the interactive effects of unilateral denervation (DN) and prolonged malnutrition (MN) on the structure and function of the diaphragm muscle (Dia). Four groups of rats were studied: control (Con), MN, DN, and DN-MN. MN began 2 wk after DN and lasted 4 wk. In both the DN and DN-MN groups, the relative loss in Dia weight exceeded the relative change in body weight. Compared with the Con group, Dia specific force was reduced by ~40% in both the DN and DN-MN groups but was unaffected in the MN group. Dia fatigue resistance improved in all experimental groups but to a greater extent in the DN and DN-MN groups. In both the DN and DN-MN groups, ~50% of Dia fibers were classified as type IIc, whereas fiber type proportions did not change in the MN group. In the DN group, only type IIb/x fibers atrophied, whereas all fiber types atrophied in the MN and DN-MN groups. We conclude that in the DN-MN group the reduction in specific force combined with the reduction in total cross-sectional area of the muscle significantly curtails Dia force-generating capacity.
KW - diaphragm contractility
KW - diaphragm fiber cross-sectional area
KW - diaphragm fiber type proportions
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U2 - 10.1152/jappl.1996.81.5.2165
DO - 10.1152/jappl.1996.81.5.2165
M3 - Article
C2 - 8941542
AN - SCOPUS:0029828782
SN - 8750-7587
VL - 81
SP - 2165
EP - 2172
JO - Journal of applied physiology
JF - Journal of applied physiology
IS - 5
ER -