Investigation of effect of NADPH inhibitors on ischemic reperfusion injury based on the NOD2 signaling pathway

Objective To investigate effect and its mechanism of NADPH inhibitors on ischemia/reperfusion injury(IRI)based on the nucleotide-binding oligomerization domain-2 (NOD2) signaling pathway. Methods Male Wistar rats with right kidney excised and were randomly divided into 4 groups:(1)renal ischemic reperfusion(I/R) group:the IRI model was prepared by clamping the left renal artery after pretreatment with the same amount of normal saline; (2)I/R + diphenylene iodonium (DPI) group:the IRI model was prepared by clamping the left renal artery after pretreatment with DPI; (3) I/R + 4-hydroxy-3-methoxyacetophenone (Apocynin) group:after pretreatment with Apocynin the IRI model of kidney was prepared by clamping the left renal artery; (4)Sham group:left renal artery was not clamped after pretreatment with the same amount of saline was given. Twenty-four hours after completion of the test, blood and kidney tissue specimens from each rat group were collected. Western blotting was used to detect the expression of renal pattern recognition receptor (NOD2), nuclear factor-κB(NF-κB) protein and cysteine protease (Caspase-1). The expression of NOD2 mRNA was detected by real-time quantitative PCR. HE staining was used to observe the histological changes of the kidney; immunohistochemistry was used to detect the expression of the inflammatory factor IL-1β in renal tissues. Results Compared with the sham group, the expression of NOD2, NF-κB protein and caspase-1 in renal tissues of rats in the I/R group increased (P<0.05); the expression of NOD2 mRNA increased (P<0.05). HE staining showed renal tubular epithelial cell edema, necrosis, shedding in the lumen, renal interstitial inflammatory cell infiltration, and a significant increase in renal tubular injury score (P<0.05). Compared with the I/R group, NOD2, NF-κB protein and caspase-1 expressions were decreased in the I/R+Apocynin group and I/R+DPI group (P<0.05); NOD2 mRNA expression was decreased (P<0.05); HE staining indicated that the degree of acute tubular necrosis was reduced by HE staining, and the score of renal tubular injury was decreased (P<0.05). Conclusions Inhibition of oxidative stress can attenuate renal ischemia-reperfusion injury by blocking the NOD2 receptor signaling pathway.