Effects of inflammation-associated acute-phase response on hepatic and renal indices in the horse

Objectives: To determine the effect of an acute soft tissue inflammatory response on biochemical and haematological indices of hepatic and renal function in the Thoroughbred horse.

Procedure: Soft tissue inflammation was induced in four Thoroughbred horses by intramuscular injections of Freund's complete Adjuvant. The horses were clinically examined and blood and urine samples were collected before and after the Adjuvant injections. Biochemical and haematological indices were measured in samples collected and used to determine the onset of the acute-phase response and to assess hepatic and renal function at this time.

Results: After Adjuvant injection, significant increases (P < 0.01) in total white (13.1 +/- 1.4 x 10(9)/L) and neutrophil (10.2 +/- 1.2 x 109/L) cell counts, rectal temperature (39.7 +/- 0.5 degrees C) and various plasma protein concentrations, including fibrinogen (6.6 +/- 1.2 g/L), haptoglobin (1.3 +/- 0.1 g/L) and total protein (88.1 +/- 2.7 g/L), indicated the induction of an acute-phase response. This corresponded with significant reductions (P < 0.01) in the plasma elimination half-lives (t1/2 beta) sodium bromosulphthalein (3.13 +/- 0.05 to 2.82 +/- 0.07 min) and sodium sulphanilate (38.29 +/- 4.04 to 19.60 +/- 5.68 min) and reductions in the plasma activities of aspartate aminotransferase, glutamate dehydrogenase, creatine kinase, Alkaline Phosphatase, gamma glutamyl transferase; the urinary creatinine clearance ratios of sodium, chloride and potassium; and the urinary gamma glutamyl transferase-to-creatinine clearance ratios. (All values mean +/- SD.)

Conclusions: The effects of the acute-phase response on indices of hepatic and renal function in the horse suggest that the disposition of pharmacological agents administered at this time may be altered and that indices of acute inflammation should be interpreted cautiously.