Objective:To evaluate the role of histone deacetylase 6 (HDAC6) in reduction of intestinal ischemia-reperfusion (I/R) injury by sodium butyrate in mice.Methods:Twenty-four SPF healthy adult male C57BL/6 mice, aged 8-10 weeks, weighing 22-25 g, were divided into 4 groups ( n=6 each) by the random number table method: sham operation group (S group), intestinal I/R group (I/R group), intestinal I/R + sodium butyrate group (I/R+ SB group), and intestinal I/R + ITSA-1+ sodium butyrate group (I/R+ I+ SB group). The model of intestinal I/R injury was established by clipping superior mesenteric artery for 45 min followed by 120 min of reperfusion in anesthetized animals.In I/R+ I+ SB group, the HDACs activator ITSA-1 0.5 mg/kg was intraperitoneally injected at 6, 3 and 1 days before ischemia.Sodium butyrate 500 mg/kg was given by intragastric administration every day one week before ischemia in I/R+ SB group and I/R+ I+ SB group, and the equal volume of normal saline was given in S group and I/R group.At 120 min of reperfusion, the mice were sacrificed and their small intestine tissues were obtained.The levels of diamine oxidase (DAO) in serum and intestinal tissues were detected by enzyme-linked immunosorbent assay.The pathological changes of small intestinal tissues were observed with a light microscope, and intestinal damage was assessed and scored according to Chiu.The expression of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ), P62 and HDAC6 was determined by Western blot.The contents of histone H3 (H3) and acetylated histone H3 (Ac-H3) in small intestinal tissues were determined by enzyme-linked immunosorbent assay. Results:Compared with S group, the Chiu′s score, levels of DAO in serum and small intestinal tissues were significantly increased, the expression of LC3 Ⅱ and HDAC6 was up-regulated, P62 expression was down-regulated, H3 content was increased, and AC-H3 content was decreased in I/R group ( P<0.05). Compared with I/R group, the Chiu′s score, levels of DAO in serum and small intestinal tissues were significantly decreased, the expression of LC3 Ⅱ and HDAC6 was down-regulated, P62 expression was up-regulated, H3 content was decreased, and AC-H3 content was increased in I/R+ SB group ( P<0.05). Compared with I/R+ SB group, the Chiu′s score and levels of DAO in serum and small intestinal tissues were significantly increased, the expression of LC3 Ⅱ and HDAC6 was up-regulated, P62 expression was down-regulated, H3 content was increased, and AC-H3 content was decreased in I/R+ I+ SB group ( P<0.05). Conclusions:Sodium butyrate can alleviate intestinal I/R injury by inhibition of HDAC6 activity in mice, and the mechanism may be related to inhibition of autophagy and promotion of H3 acetylation.

Objective:To evaluate the role of histone deacetylase (HDAC) in sodium butyrate-induced reduction of intestinal ischemia-reperfusion (I/R) injury in mice and the relationship with oxidative stress and cell apoptosis.Methods:Twenty-four SPF healthy male C57BL mice, aged 6-8 weeks, weighing 22-25 g, were divided into 4 groups ( n=6 each) according to the random number table method: sham operation group (S group), intestinal I/R group (IR group), intestinal I/R+ sodium butyrate group (IN group) and intestinal I/R+ ITSA-1+ sodium butyrate group (INI group). In IR, IN and INI groups, the superior mesenteric artery was clamped for 45 min, followed by reperfusion for 2 h to prepare the model of intestinal I/R injury, while the superior mesenteric artery was only isolated without ligation in S group.One week before preparation of the model, sodium butyrate 500 mg/kg was intragastrically administered once a day in IN group and INI group, the HDAC activator ITSA-1 0.5 mg/kg was intraperitoneally injected three times a week in INI group, and the equal volume of normal saline was given instead in the other groups.The mice were sacrificed at 2 h of reperfusion and small intestinal tissues were obtained for microscopic examination of the pathological changes which were assessed using Chiu′s score and for determination of the content of MDA (by enzyme-linked immunosorbent assay) and expression of cleaved caspase-3 (by Western blot). Results:Compared with S group, Chiu′s score was significantly increased, and the expression of cleaved caspase-3 was up-regulated in IR, IN and INI groups, the content of MDA in small intestinal tissues was significantly increased in IR and INI groups ( P<0.05). Compared with IR group, Chiu′s score was significantly decreased in IN and INI groups, and the content of MDA was significantly decreased, and the expression of cleaved caspase-3 was down-regulated in IN group ( P<0.05). Compared with IN group, Chiu′s score and content of MDA were significantly increased, and the expression of cleaved caspase-3 was up-regulated in INI group ( P<0.05). Conclusions:HDAC is involved in sodium butyrate-induced reduction of intestinal I/R injury in mice, which is related to the inhibition of oxidative stress and cell apoptosis.

AIM: To verify the role of tetramethylpyrazine (TMP) in intestinal ischemia-reperfusion (I/ R) injury and its relationship with pyroptosis. METHODS: Thirty-six healthy SPF male C57BL / 6 mice, 8-12 weeks old, weighing 20-25 g, were divided into six groups randomized by table of random number (n = 6/group): Sham group (S1 group)Ischemia/reperfusion group (I/R1 group), I/R + TMP treatment group: 15 mg/kg (T15 group), 30 mg/kg (T30 group), 60 mg/kg (T60-1 group), 120 mg/kg (T120 group). In experiment 2, thirty healthy SPF male C57BL/6 mice were divided into five groups (n = 6/group): Sham group (S2 group), I/R group (I/ R2 group), I/R + dimethyl sulphoxide (DMSO) group (DMSO group), I/R + TMP (60 mg/kg) group (T60-2 group), and I/R + DMSO + TMP (60 mg/kg) + Nigericin sodium salt (NSS) group (T60+NSS group). I/R-induced intestinal injury was established by clamping the superior mesenteric artery for 45 minutes, followed by 120 minutes of reperfusion, while the sham group mice underwent isolation of superior mesenteric artery without clamping. An NLRP3 agonist NSS was dissolved in DMSO, was intraperitoneally injected (4 mg/kg) 60 minutes before ischemia. And DMSO group mice were intraperitoneally administered with corresponding DMSO. Different TMP dosage groups and T60+NSS group mice were intraperitoneally administered with TMP 30 minutes before ischemia. IL-1β and IL-18 concentrations in the intestine were measured at 120 minutes after reperfusion by ELISA. The pathological changes of the sections were observed by optical microscope, and the intestinal mucosal injury was evaluated by Chiu's score grading. Western blot was used to detect NLRP3, Caspase-1, and GSDMD in intestinal tissue. RESULTS: Statistically significant increase of Chiu's score, IL-1β, IL-18 concentrations in the I/R1 group were found as compared with S1 group (P<0.05). And compared with I / R1 group, Chiu's score and IL-1β, IL-18 concentrations in the T60-1, T120 groups were reduced (P<0.05). Moreover, Chiu's score in the T120 group was lower than that in the T60 group (P<0.05). We found a statistically significant increase of Chiu's score and IL-1β, IL-18 concentrations and the expression of NLRP3, GSDMD, caspase-1 in the I/R group (P<0.05) as compared with S2 group. Compared with I / R2 group, Chiu's score, IL-1β, IL-18 concentrations and NLRP3, GSDMD, caspase-1 expression in the T60-2 group was reduced (P<0.05). Compared with T60-2 group, Chiu's score, IL-1β, IL-18 concentrations and NLRP3, GSDMD, caspase-1 expression in the T60 + NSS group were upregulated (P<0.05). CONCLUSION: The protective effect of TMP against intestinal I / R injury was dose-dependent. And TMP can decrease pyroptosis mainly by inhibiting the activation of the NLRP3 inflammasome.