Can L(+)-lactate be used as a marker of experimentally induced inflammation in rats?
OBJECTIVE
The purpose of this study was to investigate if L(+)-lactate (lactate) can be used as a marker of progression of joint inflammation in comparison with a reference marker, prostaglandin E2 (PGE(2)), and to analyse implications for drug treatments.


METHODS
The assessment of the inflammation time course and the treatment efficacy studies were performed on two occasions. At specific time points, synovial fluid was extracted from Sprague-Dawley rats (n = 87) challenged with either carrageenan (Cg) or Freund's complete adjuvant (FCA) or from six non-inflamed rats. Naproxen (7.5 or 30 micromol/kg) or rofecoxib (30 micromol/kg) was administered per os 2 h post Cg or at 48 h post FCA. Levels of PGE(2) and lactate were assessed either by immuno-assay or by colorimetric assay.


RESULTS
Increased levels of both markers were detected following Cg or FCA injection. Pharmacological treatments resulted in lower concentrations of PGE(2) whereas levels of lactate remained unaffected compared to the vehicle-treated group.


CONCLUSIONS
Our results suggest that lactate may be useful as an additional biomarker of inflammatory processes, especially for monitoring the non-cox-inhibitor sensitive cascade.
Finn
Anja
A
Disease Biology, Local Discovery Research Area CNS and Pain Control, AstraZeneca R&D Södertälje, Södertälje, Sweden. anja.finn@astrazeneca.com
Oerther
Sandra Claudine
SC
D000818:Animals; D001169:Arthritis, Experimental / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002351:Carrageenan; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D015232:Dinoprostone / Q000096:biosynthesis / Q000235:genetics; D004487:Edema / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D005620:Freund's Adjuvant; D007596:Joints / Q000473:pathology; D019344:Lactic Acid / Q000378:metabolism*; D007783:Lactones / Q000494:pharmacology; D008297:Male; D009288:Naproxen / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013450:Sulfones / Q000494:pharmacology
D015415:Biomarkers; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007783:Lactones; D013450:Sulfones; C116926:rofecoxib; D019344:Lactic Acid; D009288:Naproxen; D002351:Carrageenan; D005620:Freund's Adjuvant; D015232:Dinoprostone