Investigation of TNF-α and SAA Levels in the Pathogenesis of Time-Related Inflammatory Reaction in Zebrafish (Danio rerio)

Zebrafish (Danio rerio) are valuable model organisms for studying inflammation. This study aimed to evaluate the role of TNF-α and SAA in time-dependent inflammatory responses using histopathological, immunohistochemical, and ELISA techniques. One-year-old wild-type zebrafish were divided into five groups (n=20). Group 1 (G-1) received intraperitoneal (IP) injections of 0.9% NaCl, while Groups 2-5 were treated with Complete Freund`s Adjuvant and Keyhole Limpet Hemocyanin. G-2 and G-3 received a single dose on day 0 to model peracute and acute inflammation, while G-4 and G-5 received two doses on days 0 and 14 to model subacute and chronic inflammation. Blood and spleen samples were collected for further analysis. The highest TNF-α and SAA immune-positivity intensity (IPI) scores were observed in G-4 and G-5, with staining in the perifollicular macrophages and lymphocytes. Plasma TNF-α peaked in G-4 (21.435±3.783 ng/L), and SAA in G-5 (1.657±0.218 μg/ml). Significant correlations between TNF-α and SAA levels were found in G-2 (P