Effects of Apocynin, a NADPH Oxidase Inhibitor, in the Protection of the Heart from Ischemia/Reperfusion Injury

by Selleckchem | Sep 12 2023

Ischemia and perfusion (I/R) induce inflammation and oxidative stress, which play a notable role in tissue damage. The aim of this study was to investigate the role of an NADPH oxidase inhibitor (apocynin) in the protection of the heart from I/R injury. Hearts isolated from Wistar rats (n = 8 per group) were perfused with a modified Langendorff preparation. Left ventricular (LV) contractility and cardiovascular hemodynamics were evaluated by a data acquisition program, and infarct size was evaluated by 2,3,5-Triphenyl-2H-tetrazolium chloride (TTC) staining. Furthermore, the effect of apocynin on the pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) and anti-inflammatory cytokine (IL-10) was evaluated using an enzyme linked immunosorbent assay (ELISA). Hearts were subjected to 30 min of regional ischemia, produced by ligation of the left anterior descending (LAD) coronary artery, followed by 30 min of reperfusion. Hearts were infused with apocynin before ischemia, during ischemia or at reperfusion. To understand the potential pathways of apocynin protection of the heart, a nitric oxide donor (S-nitroso-N-acetylpenicillamine, SNAP), nitric oxide blocker (N (gamma)-nitro-L-arginine methyl ester, L-Name), nicotinic acid adenine dinucleotide phosphate (NAADP) inhibiter (Ned-K), cyclic adenosine diphosphate ribose (cADPR) agonist, or CD38 blocker (Thiazoloquin (az)olin (on)e compound, 78c) was infused with apocynin. Antioxidants were evaluated by measuring superoxide dismutase (SOD) and catalase (CAT) activity. Apocynin infusion before ischemia or at reperfusion protected the heart by normalizing cardiac hemodynamics and decreasing the infarct size. Apocynin treatment resulted in a significant (p < 0.05) decrease in pro-inflammatory cytokine levels and a significant increase (p < 0.05) in anti-inflammatory and antioxidant levels. Apocynin infusion protected the heart by improving LV hemodynamics and coronary vascular dynamics. This treatment decreased the infarct size and inflammatory cytokine levels and increased anti-inflammatory cytokine and antioxidant levels. This protection follows a pathway involving CD38, nitric oxide and acidic stores.

Comments:

The study aimed to investigate the protective effects of an NADPH oxidase inhibitor called apocynin in ischemia/reperfusion (I/R) injury of the heart. Ischemia and reperfusion can lead to tissue damage through the induction of inflammation and oxidative stress. The researchers used a modified Langendorff preparation to perfuse hearts isolated from Wistar rats.

The evaluation of left ventricular contractility, cardiovascular hemodynamics, and infarct size was carried out using a data acquisition program and 2,3,5-Triphenyl-2H-tetrazolium chloride (TTC) staining, respectively. The effects of apocynin on pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) and an anti-inflammatory cytokine (IL-10) were assessed using an enzyme-linked immunosorbent assay (ELISA). The hearts underwent 30 minutes of regional ischemia, induced by ligation of the left anterior descending (LAD) coronary artery, followed by 30 minutes of reperfusion. Apocynin was infused before ischemia, during ischemia, or at reperfusion. To understand the potential mechanisms of apocynin's protection, additional substances were infused along with apocynin, including a nitric oxide donor (S-nitroso-N-acetylpenicillamine, SNAP), nitric oxide blocker (N (gamma)-nitro-L-arginine methyl ester, L-Name), nicotinic acid adenine dinucleotide phosphate (NAADP) inhibitor (Ned-K), cyclic adenosine diphosphate ribose (cADPR) agonist, or CD38 blocker (Thiazoloquin (az)olin (on)e compound, 78c).

The activity of antioxidants, specifically superoxide dismutase (SOD) and catalase (CAT), was evaluated. The results showed that infusion of apocynin before ischemia or at reperfusion protected the heart by restoring normal cardiac hemodynamics and reducing the size of the infarct. Apocynin treatment significantly decreased the levels of pro-inflammatory cytokines and increased the levels of anti-inflammatory cytokines and antioxidants.

The protective effects of apocynin involved the improvement of left ventricular hemodynamics and coronary vascular dynamics. The treatment reduced infarct size, lowered inflammatory cytokine levels, and increased anti-inflammatory cytokine and antioxidant levels. The protection mechanism appeared to involve CD38, nitric oxide, and acidic stores.

In conclusion, the study demonstrated that apocynin infusion provided protection to the heart against I/R injury by mitigating inflammation, enhancing antioxidant capacity, and improving cardiovascular function.