Tissue and intracellular pH in normal periarticular soft tissue and during different phases of antigen induced arthritis in the rat.
OBJECTIVE
To measure intracellular and tissue pH in periarticular soft tissue during different phases of antigen induced arthritis in the rat.


METHODS
pH was calculated using the following values: (1) the distribution of [14C]-dimethyl-oxazolidinedione; (2) the total tissue water and the extracellular space water volume, which was measured as [14C]-sucrose distribution in nephrectomized rats. Experiments were performed during both maximal inflammation (Day 3) and the restorative phase (Day 14).


RESULTS
In all animals both tissue (pHt) and intracellular (pHi) pH were lower in arthritic joints than in the contralateral control. Mean pHt in control joints was 7.37+/-0.03. In arthritic rats it was 7.30+/-0.05 on Day 3 after challenge and 7.27+/-0.03 on Day 14. The pHi ranges were 6.86-7.81 for controls, 6.65-7.28 for arthritis Day 3, and 5.66-6.91 for arthritis Day 14.


CONCLUSIONS
In this model there is a reduction in pH in the periarticular tissue of arthritic joints. The magnitude is, however, relatively small and the pannus tissue is not uniquely acidic in comparison with other compartments. There does not seem to be a correlation between pH and changes in metabolic balance, pannus formation, or healing.
Andersson
S E
SE
Department of Pharmacology, Preclinical Research and Development, Astra Zeneca, Lund, Sweden.
Lexmüller
K
K
Johansson
A
A
Ekström
G M
GM
D000138:Acidosis / Q000378:metabolism*; D000818:Animals; D001168:Arthritis / Q000276:immunology / Q000378:metabolism*; D001834:Body Water / Q000378:metabolism; D002478:Cells, Cultured; D046508:Culture Techniques; D004114:Dimethadione / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D006863:Hydrogen-Ion Concentration; D007249:Inflammation / Q000378:metabolism; D007719:Knee Joint / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology; D009392:Nephrectomy; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013395:Sucrose / Q000378:metabolism; D013997:Time Factors
D013395:Sucrose; D004114:Dimethadione