Issn Print: 0195-9131
Publication Date: 1997/05/01
TIME COURSE STUDY OF AGE-INDUCED CONTRACTILE DYSFUNCTION IN THE MAMMALIAN DIAPHRAGM 1646
A. M. Maxwell; R. A. Herb; R. A. Shanely; J. Stears; J. Frisbie; S. Ristow; L. Mieding; J. R. Coast
Excerpt
Previous studies have demonstrated a maximal isometric specific force(PO) deficit in the senescent rat diaphragm (DIA). However the time course associated with the reduction in DIA PO has not been characterized. The current study tested the hypothesis that DIA PO would exhibit a progressive decrease as a function of increasing age. Male, specific pathogen-free, barrier protected (SPFB) Fisher-344 rats (n=26) were obtained from the National Institute of Aging colony. Animals at 4mo., 9mo., 12mo., 18mo., and 26months were evaluated for diaphragmatic specific PO using an in vitro field-stimulated strip preparation. Maximal specific PO of diaphragms from 18mo. (23.6 N·cm-2;-19.3%) and 26mo. (23.0 N·cm-2;-21.2%) animals were significantly(p<0.05) lower relative to the 4mo. (29.2 N·cm-2) group. Further, 9mo. (28.9 N·cm-2;-1.1%) and 12 mo. (28.5 N·cm-2;-19.3%) animals exhibited small, nonsignificant changes in specific PO when compared to the 4mo. group. These data do not support the hypothesis that a progressive reduction in DIA specific PO exists over the lifespan of the male, SPFB Fisher-344 rat. Rather, a significant detriment in the [Illegible Text] generating capacity of the aging DIA was observed only in 18mo. and 26mo. animals. Future studies are necessary to elucidate the mechanisms associated with the observed force deficit.
Facebook
Twitter
LinkedIn
Email
