LAUSR

Aldehyde reductase (ALR) plays key roles in the detoxification of toxic aldehyde. In this study, we cloned the swamp eel ALR gene using RACE-PCR. The recombinant protein (rALR) was expressed in E.coli and purified using a Ni2+ -NTA chelating column. The rALR protein exhibited efficient reductive activity toward several aldehydes, ketones, and S-nitrosoglutathione (GSNO). A spot assay suggested that the recombinant E.coli strain expressing rALR had better resistance to formaldehyde, sodium nitrite, and GSNO stress, suggesting that swamp eel ALR is crucial for redox homeostasis in vivo. Consequently, we investigated the effect of rALR on the oxidative parameters of the liver in swamp eels challenged with Aeromonas hydrophila. The hepatic GSH content was significantly increased, and the hepatic NO content and levels of reactive oxygen species and reactive nitrogen species were significantly decreased when rALR was administered. In addition, the mRNA expression of hepatic Alr, HO1, and Nrf2 was significantly upregulated, while the expression levels of NF-κB, IL-1β, and Nos1 were significantly downregulated in the rALR-administered group. Collectively, these results suggest that ALR is involved in the response to nitrosative stress by regulating GSH/NO levels in the swamp eel. This article is protected by copyright. All rights reserved.