Forty-eight SD rats were randomly divided into eight groups (n = 6 per group): sham, IIR model, sham+Lipoxin A4 (LXA4), IIR+LXA4, sham+LXA4+Boc-2 (Boc-2, C44H59N5O8, a LXA4 antagonist, Figure 1 ), IIR+LXA4+Boc-2, sham+LXA4+brusatol (Bru., C26H32O11, a Nrf2 antagonist, Figure 1 ), and IIR+LXA4+Bru.
First, to evaluate the effects of Lipoxin A4 on IIR injury, Lipoxin A4 (100 μg/kg [22 (link)]) (Cayman Chemical Company, Ann Arbor, USA) was dissolved in normal saline 2 mL/kg and administrated via tail vein 15 min before intestine ischemia in IIR+LXA4, IIR+LXA4+Boc-2, and IIR+LXA4+Bru groups, and the same dose of Lipoxin A4 was also given in sham+LXA4 as a control. Next, to detect the role of Lipoxin A4 receptor in the protective effects of Lipoxin A4, Lipoxin A4 receptor antagonist Boc-2 (50 mg/kg [23 (link)], i.p., Phoenix Pharmaceuticals, Phoenix, AZ) was given 10 min before Lipoxin A4 administration in IIR+Boc-2 and IIR+LXA4+Boc-2 groups. Boc-2 was also given in sham+LXA4+Boc-2 as a control. Finally, to expose the role of Nrf2 pathway in Lipoxin A4-conferred intestinal mucosa protection, Nrf2 antagonist brusatol (0.4 mg/kg [24 (link)], i.p., BOC Sciences, Shirley, NY, USA) was administrated every other day for a total of five times before surgery in IIR+LXA4+Bru group. Brusatol was also given in sham+LXA4+Bru as a control.
First, to evaluate the effects of Lipoxin A4 on IIR injury, Lipoxin A4 (100 μg/kg [22 (link)]) (Cayman Chemical Company, Ann Arbor, USA) was dissolved in normal saline 2 mL/kg and administrated via tail vein 15 min before intestine ischemia in IIR+LXA4, IIR+LXA4+Boc-2, and IIR+LXA4+Bru groups, and the same dose of Lipoxin A4 was also given in sham+LXA4 as a control. Next, to detect the role of Lipoxin A4 receptor in the protective effects of Lipoxin A4, Lipoxin A4 receptor antagonist Boc-2 (50 mg/kg [23 (link)], i.p., Phoenix Pharmaceuticals, Phoenix, AZ) was given 10 min before Lipoxin A4 administration in IIR+Boc-2 and IIR+LXA4+Boc-2 groups. Boc-2 was also given in sham+LXA4+Boc-2 as a control. Finally, to expose the role of Nrf2 pathway in Lipoxin A4-conferred intestinal mucosa protection, Nrf2 antagonist brusatol (0.4 mg/kg [24 (link)], i.p., BOC Sciences, Shirley, NY, USA) was administrated every other day for a total of five times before surgery in IIR+LXA4+Bru group. Brusatol was also given in sham+LXA4+Bru as a control.