METHODOLOGICAL AND FUNCTIONAL-ASPECTS OF THE ISOLATED BOVINE RUMEN EPITHELIUM IN USSING CHAMBER FLUX STUDIES

Citation
J. Sehested et al., METHODOLOGICAL AND FUNCTIONAL-ASPECTS OF THE ISOLATED BOVINE RUMEN EPITHELIUM IN USSING CHAMBER FLUX STUDIES, Acta agriculturae Scandinavica. Section A, Animal science, 46(2), 1996, pp. 76-86
Citations number
18
Categorie Soggetti
Agriculture Dairy & AnumalScience
ISSN journal
09064702
Volume
46
Issue
2
Year of publication
1996
Pages
76 - 86
Database
ISI
SICI code
0906-4702(1996)46:2<76:MAFOTI>2.0.ZU;2-S
Abstract
The properties of isolated sheets of bovine rumen epithelium in the Us sing chamber system were studied. The viability and time-dependent cha nge in performance, as expressed by electrical parameters, was accepta ble and comparable to what has been obtained with other epithelia in v itro. The viability and time-dependent change in performance was not i nfluenced by transport time (5 to 45 minutes) between the slaughterhou se and the laboratory. Flux rates of Na-22(+) and C-14-propionate show ed that an equilibration period of 45 minutes after addition of tracer s will be sufficient to obtain steady-state conditions with this epith elium. Compared with the time-dependent changes in electrical paramete rs, this shows that rumen epithelium cannot truly be used as its own c ontrol over time. The varying papillation caused surface enlargement f actors between one and five, estimated by the dry weight of stripped e pithelium. However, the dry weight was not correlated to epithelial ca pacitance or flux rates. It is concluded that the papillae do not cont ribute significantly to the fluxes measured in vitro. and that correct ion for surface enlargement is not essential for the evaluation of flu x data. The pH was 0.27 to 0.30 units lower at the epithelial surface than in the bulk solution. and the pH difference was not influenced by glucose or SCFA free solutions, nor by Amiloride (1 mmol l(-1)). The observed lower epithelial surface pH seems not to be an acidic microcl imate in the traditional sense, but could be explained by a negatively charged surface potential of the epithelial cells.