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Objective:To evaluate the role of signal transducer and activator of transcription 3 (STAT3)/nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy in salidroside-induced attenuation of intestinal ischemia-reperfusion (I/R) injury in mice and the relationship with ferroptosis.Methods:Thirty-six SPF-grade healthy male C57BL mice, aged 6-8 weeks, weighing 20-25 g, were divided into 6 groups ( n=6 each) by a random number table method: sham operation group (S group), sham operation+ salidroside group (SS group), intestinal I/R group (IR group), intestinal I/R+ salidroside group (IS group), intestinal I/R+ salidroside+ autophagy activator rapamycin group (ISR group) and intestinal I/R+ salidroside+ STAT3 activator colivelin group (ISC group). The intestinal I/R injury model was established by clamping the superior mesenteric artery for 45 min followed by 30-min reperfusion in IR, IS, ISR and ISC groups, while the superior mesenteric artery was only isolated without clipping in S and SS groups. At 1 week before developing the model, salidroside 40 mg/kg was intraperitoneally injected once a day for 7 consecutive days in SS, IS, ISC and ISR groups, rapamycin 4 mg/kg was intraperitoneally injected once a day for 7 consecutive days in group ISR, colivelin 1 mg/kg was intraperitoneally injected once a day for 7 consecutive days in group ISC, while the equal volume of normal saline was given instead in the rest two groups. The mice were sacrificed at 30 min of reperfusion, and intestinal tissues were obtained for examination of the pathological changes after HE staining (with a optical microscope) which were scored according to Chiu and for determination of contents of malondialdehyde (MDA), Fe 2+, glutathione (GSH) and reactive oxygen species (ROS), activity of superoxide dismutase (SOD) and expression of p-STAT3, STAT3, glutathione peroxidase 4 (GPX4), NCOA4 and ferritin heavy chain 1 (FTH1) in intestinal tissues (by Western blot). Results:Compared with group S, the Chiu′s score and contents of MDA, Fe 2+ and ROS were significantly increased, the content of GSH was decreased, the activity of SOD was decreased, the expression of p-STAT3 and NCOA4 was up-regulated, the expression of GPX4 and FTH1 was down-regulated, the p-STAT3/STAT3 ratio was increased ( P<0.05), pathological injury was found in intestinal tissues, and no significant change was found in the aforementioned indexes in group IR( P>0.05). Compared with group IR, the Chiu′s score and contents of MDA, Fe 2+ and ROS were significantly decreased, GSH content was increased, SOD activity was increased, the expression of p-STAT3 and NCOA4 was down-regulated, the expression of GPX4 and FTH1 was up-regulated, p-STAT3/STAT3 ratio was decreased ( P<0.05), and the pathological injury was significantly alleviated in intestinal tissues in group IS. Compared with group IS, the Chiu′s score and contents of MDA, Fe 2+ and ROS were significantly increased, GSH content was decreased, SOD activity was decreased, the expression of p-STAT3 and NCOA4 was up-regulated, the expression of GPX4 and FTH1 was down-regulated, p-STAT3/STAT3 ratio was increased ( P<0.05), and the pathological injury was aggravated in intestinal tissues in ISR and ISC groups. There was no statistically significant difference in the expression of STAT3 among the five groups ( P>0.05). Conclusions:STAT3/NCOA4-mediated ferritinophagy is involved in the process of salidroside-induced reduction of intestinal I/R injury in mice, which may be related to inhibiting ferroptosis.
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Objective:To evaluate the role of endoplasmic reticulum stress-mediated apoptosis in proanthocyanidins-induced attenuation of intestinal ischemia-reperfusion (I/R) injury in mice.Methods:Thirty SPF healthy adult male C57BL/6 mice, aged 8-10 weeks, weighing 20-25 g, were divided into 5 groups ( n=6 each) by a random number table method: sham operation group (S group), sham operation + proanthocyanidins group (S+ PC group), intestinal I/R group (I/R group), intestinal I/R + proanthocyanidins group (I/R+ PC group) and intestinal I/R + proanthocyanidins + tunicamycin group (I/R+ PC+ TM group). The superior mesenteric artery was clamped for 60 min and reperfused for 120 min to establish a mouse intestinal I/R injury model.Proanthocyanidin 100 mg/kg was given by intragastric gavage every day 1 week before ischemia in S+ PC group, I/R+ PC group and I/R+ PC+ TM group, and the equal volume of normal saline was given for 7 consecutive days in S group and I/R group, and endoplasmic reticulum stress agonist tunicamycin 1 mg/kg was intraperitoneally injected at 24 h before ischemia in I/R+ PC+ TM group.The mice were sacrificed at 120 min of reperfusion, and the small intestinal tissues were taken for microscopic examination of the histopathological changes (using light microscopy) and for determination of the level of diamine oxidase (DAO) (by enzyme-linked immunosorbent assay), cell apoptosis (by TUNEL method), glucose regulatory protein 78 (GRP78), C/EBP-homologous protein (CHOP) and cleaved caspase-3, Bax and Bcl-2 (by Western blot). Intestinal damage was assessed and scored according to Chiu, and the apoptosis index (AI) and Bcl-2/Bax ratio were calculated. Results:Compared with S group, the Chiu′s score, level of DAO and AI were significantly increased, the expression of GRP78, CHOP, cleaved caspase-3 and Bax was up-regulated, the expression of Bcl-2 was down-regulated, the ratio of Bcl-2/Bax was decreased( P<0.05), and the pathological damage occurred in the small intestinal tissue in I/R group, and no significant change was found in the aforementioned indexes in S+ PC group ( P>0.05). Compared with I/R group, the Chiu′s score, DAO level and AI were significantly decreased, the expression of GRP78, CHOP, cleaved caspase-3 and Bax was down-regulated, the expression of Bcl-2 was up-regulated, the ratio of Bcl-2/Bax was increased( P<0.05), and the pathological injury to the small intestinal tissue was significantly reduced in I/R+ PC group. Compared with I/R+ PC group, the Chiu′s score, level of DAO and AI were significantly increased, the expression of GRP78, CHOP, cleaved caspase-3 and Bax was up-regulated, the expression of Bcl-2 was down-regulated, and the ratio of Bcl-2/Bax was decreased( P<0.05), and the pathological damage to the small intestinal tissue was aggravated in I/R+ PC+ TM group. Conclusions:Proanthocyanidins can alleviate intestinal I/R injury by inhibiting endoplasmic reticulum stress-mediated cell apoptosis in mice.
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Objective:To evaluate the role of silencing information regulatory factor 1/nuclear factor E2 related factor 2 (SIRT1/Nrf2) signaling pathway in berberine preconditioning-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice and the relationship with ferroptosis.Methods:Thirty-six SPF-grade healthy male C57BL/6 mice, aged 8-10 weeks, weighing 22-25 g, were divided into 6 groups ( n=6 each) by a random number table method: sham operation group (S group), sham operation + berberine preconditioning group (SB group), intestinal I/R group (IR group), intestinal I/R + berberine preconditioning group (B group), intestinal I/R + berberine preconditioning + SIRT1 inhibitor EX527 group (BE group) and berberine preconditioning + intestinal I/R + ferroptosis inducer RSL3 group (BR group). The model of intestinal I/R injury was prepared by clamping the superior mesenteric artery for 45 min followed by 30-min reperfusion in IR group, B group, BE group and BR group, while the superior mesenteric artery was only isolated without ligation in S group and SB group. Berberine 50 mg/kg was administered by intragastric gavage once a day starting from 7 days before developing the model in SB group, B group, BE group and BR group. EX527 5 mg/kg and RSL3 5 mg/kg were intraperitoneally injected once a day at 3 days before surgery in BE group and BR group, respectively. The equal volume of normal saline was given in the other groups. The mice were sacrificed at 30 min of reperfusion, and the intestinal tissues were taken for microscopic examination of the pathological changes of intestinal mucosa (with a light microscope) which was scored according to Chiu and for determination of the contents of Fe 2+ and malondialdehyde (MDA) and superoxide dismutase (SOD) activity (by colorimetry), glutathione (GSH) content (by enzyme-linked immunosorbent assay), reactive oxygen species (ROS) content (by fluorescence staining), and expression of glutathione peroxidase 4 (GPX4), SIRT1 and Nrf2 (by Western blot). Results:Compared with S group, Chiu′s score was significantly increased, the contents of Fe 2+, MDA and ROS were increased, the content of GSH and activity of SOD were decreased, the expression of GPX4 was down-regulated, and the expression of SIRT1 and Nrf2 was up-regulated in IR group ( P<0.05), and no significant change was found in Chiu′s score in SB group ( P>0.05). Compared with IR group, Chiu′s score was significantly decreased, the contents of Fe 2+, MDA and ROS were decreased, the content of GSH and activity of SOD were increased, the expression of GPX4 was up-regulated, and the expression of SIRT1 and Nrf2 was up-regulated in B group ( P<0.05). Compared with B group, Chiu′s score was significantly increased, the contents of Fe 2+, MDA and ROS were increased, the content of GSH and activity of SOD were decreased, and the expression of GPX4 was down-regulated in BE and BR groups, and the expression of SIRT1 and Nrf2 was down-regulated in BE group( P<0.05). Conclusions:The mechanism by which berberine preconditioning reduces intestinal I/R injury may be associated with activation of SIRT1/Nrf2 signaling pathway, thus inhibiting ferroptosis in mice.