The mechanism of lower limb ischemia-reperfusion injury(IRI) is closely related to inflammatory reaction, and miR-206 plays a key role in vascular inflammation. This study aims to investigate the effect of miR-206 on inflammatory response during lower limb IRI in rats.

Forty-eight male SD rats were divided into 4 groups according to the random number table: Sham group (free femoral artery, no clipping femoral artery treatment), IRI group(the rat model of lower limb IRI was established, and 0.9% sodium chloride solution was injected into tail vein), IRI+ miR-206 agomir group (miR-206 agonist miR-206 agomir group after model establishment), IRI+ miR-206 antagomir group (miR-206 antagonist miR-206 antagomir group after model establishment), with 12 rats in each group. Rats were killed after anesthesia, and the femoral artery was taken, and HE staining and pathological analysis were recorded to observe the morphological changes of femoral artery wall. Apoptosis of rat femoral artery was detected by TUNEL. Detection of oxidative stress products superoxide dismutase(SOD) and malondialdehyde(MDA) in rat femoral artery; western blotting was used to detect the expression of high mobility group B1 (HMGB1), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in rat femoral artery. Data were statistically analyzed with one-way analysis of variance and least significant difference test.

The expression level of miR-206 mRNA in IRI+ miR-206 agomir group was significantly higher than those in IRI group and IRI+ miR-206 antagomir group(t=7.81, 9.39; P<0.05), while the expression level of miR-206 mRNA in IRI+ miR-206 antagomir group was significantly lower than that in IRI group (t=5.39, P<0.05); Observation under HE staining light microscope, the ischemia-reperfusion femoral artery injury of the injured lower limbs in IRI+ miR-206 agomir group was alleviated, while the ischemia-reperfusion femoral artery injury of the injured lower limbs in IRI+ miR-206 antagomir group was aggravated. Compared with IRI group and IRI+ miR-206 antagomir group, SOD activity in IRI+ miR-206 agomir group was significantly increased(t=4.54, 8.25; P<0.05), while MDA level was significantly decreased in IRI+ miR-206 agomir group(t=4.09, 6.27; P<0.05). Compared with IRI group, SOD activity in IRI+ miR-206 antagomir group was significantly decreased(t=4.52, P<0.05), while MDA level in IRI+ miR-206 antagomir group was significantly increased (t=3.40, P<0.05). The expression levels of HMGB1, TNF-a and IL-6 were compared among the groups, and the differences were statistically significant (F=124.90, 20.05, 94.73; P<0.05); The expression levels of HMGB1、TNF-a and IL-6 of IRI+ miR-206 agomir group were significantly lower than those of IRI group and IRI+ miR-206 antagomir group(t=7.68, 17.7; t=2.59, 4.63; t=9.21, 10.32; P<0.05). The expression levels of HMGB1, IL-6 of IRI+ miR-206 antagomir group were significantly higher than that of the IRI group(t=4.26, 2.56; P<0.05).

The high expression of miR-206 can inhibit the inflammatory level during lower limb IRI in rats, which provides a way for clinical treatment of lower limb IRI.