Markers of experimental acute inflammation in the Wistar Han rat with particular reference to haptoglobin and C-reactive protein

Abstract

C-reactive protein (CRP), haptoglobin (Hp) and fibrinogen (Fbgn) are acute phase reactants (APRs), the blood levels of which increase during acute inflammation. However, although the levels of these APRs are used to monitor inflammation in man, their usefulness and sensitivity as markers of inflammation in rodents are less clear. We therefore wished to evaluate, in a comparative fashion, a prototype immunoassay for serum CRP, a commercial assay for serum Hp, and an automated assay for Fbgn, using a model of acute inflammation in the rat. Additionally, pro-inflammatory cytokines and serum protein fractions were also measured. The model of inflammation used was the intraperitoneal injection of Freund's complete adjuvant (FCA). In a concluding experiment, findings with Hp in the FCA rat model were validated in a toxicologically relevant study involving the induction of acute hepatic inflammation using the model hepatotoxicant carbon tetrachloride (CCl(4)). Female Wistar Han rats were treated with a single injection of FCA in a dose-response study (1.25-10.0 ml/kg, sampling at 36 h) and two time-course studies (over 40 h and 21 days). In a final experiment, rats were dosed with CCl(4) at 0.8 ml/kg and sampled over a 17-day period. In FCA and CCl(4) experiments, serum/plasma was prepared and tissues taken at autopsy for histological assessment (CCl(4) study only). In the dose-response study, serum CRP, Hp and plasma Fbgn were increased at all FCA dose levels at 36 h post-dosing. Serum alpha(2) and beta(1) globulin fractions were also increased, while albumin levels were decreased. In the 40-h time-course study, CRP levels peaked at 25-40 h post-dosing, to approximately 120% of control (as 100%). Hp levels increased to a maximum at 25 and 40 h post-dosing with values greater than 400% of control, and alpha(2) and beta(1) globulin fractions peaked at 30 and 40 h post-dosing to 221 and 187% of control, respectively. Increased serum interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) levels peaked at 20 h (11-fold) and 25 h (19-fold), respectively. In a 21-day time-course study, no increased CRP levels were measured despite elevated levels of Hp, which peaked at 36 h (approximately 7-fold above control), and remained elevated up to 21 days. IL-6 and IL-1beta levels peaked at 12 h (19-fold) and 24 h (28-fold), respectively. Liver histopathology of animals treated with CCl(4) showed centrilobular hepatocellular degeneration and necrosis (most significant at 36 h) with an inflammatory response (most significant at 48 h). Resolution of the lesion was complete by 4 days post-dosing. Serum alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase levels peaked at 36 h post-dosing. Hp levels increased maximally at 48 h (426% of control). We conclude that serum CRP is a poor marker of acute inflammation in the rat in comparison with serum Hp and plasma Fbgn. Between Hp and Fbgn, serum Hp is shown to be the most sensitive and useful marker of acute inflammation.

Exercise maintains euglycemia in association with decreased activation of c-Jun NH2-terminal kinase and serine phosphorylation of IRS-1 in the liver of ZDF rats

“…As another inflammatory marker, we measured haptoglobin, rather than CRP, because CRP is not an ideal measurement of the liver's response to inflammatory status in rats (34). Plasma haptoglobin levels were significantly less in E than in S rats by 4 wk of intervention and remained below levels in S rats throughout the rest of the study (Fig.…”

Acute Phase Protein Response in the Capybara (Hydrochoerus Hydrochaeris)

“…Haptoglobin peaked at 2 wk. In rats, a faster response has been reported for Hp, achieving maximum values 24 hr after an inflammatory stimulus (Deak et al, 1997;Kataranovski et al, 1999;Giffen et al, 2003;Matić et al, 2004). Nevertheless, the magnitude of the increase observed in Hp was similar to other studies in rats (Matić et al, 2004).…”

The effects of immunosuppressive agents on inflammatory response in septic rats

“…Some studies indicate that cytokines, such as TNF-α, induced rat liver cell cytotoxicity, and the AST level increased at the 12 th hour and reaching its maximum level at the 36 th hour [31,33]. In our study, AST levels were used as the indicator of liver toxicity and organ failure.…”

“…In some trials, it has been demonstrated that CRP levels rise in a statistically significant manner and are an indicator of inflammation [30,31]. Kuster et al [32] have reported that, while the diagnostic sensitivity of CRP before the clinical appearance of peritonitis is 18%, its sensitivity is 93% at the time of the clinical diagnosis.…”