To observe the ameliorative effect of inhibiting acetyl-CoA carboxylase 2(ACC2) on cardiac dysfunction in septic mice and investigate its underlying mechanism.

Mouse model of sepsis was established by cecal ligation and perforation.A total of 24 male C57BL/6 mice (aged 8 weeks, weighing 20~25 g) were divided into sham operation group, sepsis group and ND-630+sepsis group.The cardiac specific ACC2 knockout (ACC2^ΔCM) mice were constructed by Cre-LoxP recombinase system, and ACC2^flox/flox Myh6-Cre^-(ACC2^fl/fl) mice were used as control.Several genetically engineered mice (8 weeks old, 20~25 g, male) were divided into ACC2^fl/fl+sham operation group, ACC2^fl/fl+sepsis group, ACC2^ΔCM+sepsis group, ACC2^ΔCM+Mal-CoA+sepsis group, and ACC2^ΔCM+sham operation group according to the random number table method.The contractile function and myofilament calcium sensitivity of cardiomyocytes were measured by a cell microtensiometer.Western blotting was used to detect the expression level of ACC2, and ELISA was employed to measure the level of malonyl-CoA (Mal-CoA) in myocardial tissue.The survival of the mice in 36 h after sepsis was observed.

Compared with the sham operation group, the contraction amplitude of cardiomyocytes in sepsis group was decreased markedly, and the calcium sensitivity decreased significantly as well (P < 0.05).Based on the ACC2^fl/fl+sham operation group, the ACC2^ΔCM+sepsis group showed significant improvement in myocardial contraction compared with the ACC2^fl/fl+sepsis group, with the contraction amplitude of cardiomyocytes recovered by 48.1%, and significantly restored calcium sensitivity (P < 0.05).ACC2^ΔCM+Mal-CoA+sepsis group showed a notable decrease in myocardial cell contraction amplitude and a significant decrease in calcium sensitivity when compared to the ACC2^ΔCM+sepsis group (P < 0.05).Compared with the sepsis group, the contraction amplitude of cardiomyocytes in the ND-630+sepsis group increased significantly, and the calcium sensitivity of myofilament also increased (P < 0.05).The expression level of ACC2 protein in the myocardial tissue of mice in the sepsis group increased compared to the sham operation group (P < 0.05).The level of myocardial Mal-CoA in the sepsis group was higher than that in the sham operation group (P < 0.05);Mal-CoA level in the myocardium of ACC2^ΔCM+sepsis group mice was lower than that of sepsis group (P < 0.05).The 36-hour survival rate of the ACC2^ΔCM+sepsis group.mice was 37.5% higher than that of the ACC2^fl/fl+sepsis group mice.(P < 0.05).

Inhibition of ACC2 exerts a protective effect on myocardial contractility and calcium sensitivity in septic mice by reducing Mal-CoA.

To investigate the protective effects of remimazolam (Remi), a novel benzodiazepine sedative, on intestinal barrier function in septic mice.

A mouse model of sepsis was established using cecal ligation and puncture (CLP). A total of 96 SPF-grade adult male C57BL/6 mice were randomized into sham operation (Sham), sepsis (Sepsis), and sepsis with Remi intervention (Sepsis+Remi) groups. Survival rate and survival time were recorded within 72 h after modeling. Intestinal pathological alterations, barrier functional indicators, ZO-1 expression, and macrophage polarization status were observed and detected to evaluate the effects of Remi. Lipopolysaccharide (LPS) was used to treat RAW264. 7 cells for 24 h to simulate in vitro sepsis model. The cells were divided into control (Control), LPS, and LPS+Remi groups. Immunofluorescence staining was performed to assess macrophage phenotype, mitochondrial morphology, and mitochondrial reactive oxygen species (MtROS), and Western blotting was applied to detect the protein expression of iNOS and CD206.

Compared with the sepsis group, Remi intervention significantly improved the survival rate of septic mice from 12. 50% to 68. 75% and markedly prolonged survival duration (P<0. 05). Histopathological analysis demonstrated partial restoration of intestinal villus architecture, accompanied with attenuated interstitial edema and reduced inflammatory cell infiltration after Remi intervention. Furthermore, the intervention group demonstrated significant improvement in functional indicators. Both in vivo and in vitro experiments demonstrated elevated iNOS and decreased CD206 expression in the septic mice and LPS-stimulated macrophages (P<0. 05), which were partially reversed after Remi intervention. Furthermore, LPS-stimulated macrophages exhibited fragmented mitochondria and elevated MtROS level, whereas Remi intervention ameliorated these conditions (P<0. 05).

Remi protects intestinal barrier function in septic mice by mitigating mitochondrial dynamics imbalance-induced oxidative damage and ameliorating inflammatory macrophage activation.