Activation of vagovagal reflex prevents hepatic ischaemia-reperfusion-induced lung injury via anti-inflammatory and antioxidant effects.

NEW FINDINGS: What is the central question of this study? Does vagus nerve stimulation have protective effects against both direct liver damage and distant lung injury in a rat model of hepatic ischaemia-reperfusion? What is the main finding and its importance? Vagus nerve stimulation provides protection through anti-inflammatory and anti-oxidative stress effects, possibly achieved by the vagovagal reflex. ABSTRACT: Hepatic ischaemia-reperfusion (I/R) is not an isolated event; instead, it can result in remote organ dysfunction. The aim of this study was to investigate whether vagus nerve stimulation (VNS) can alleviate hepatic I/R-induced lung injury and to explore the underlying mechanism. Thirty male Sprague-Dawley rats were randomly allocated into five groups (n = 6 each): the sham group (without I/R or VNS), the I/R group (hepatic I/R) and three different VNS treatment groups (hepatic I/R plus VNS). The hepatic I/R group was subjected to occlusion of the portal vein and hepatic artery for 1 h, followed by 6 h of reperfusion. The intact afferent and efferent cervical vagus nerves were stimulated throughout the I/R process. During VNS, cervical neural activity was recorded. At the end of the experiment, liver function, the wet-to-dry lung weight ratio, histology of the liver and lung and inflammatory/oxidative indices were evaluated. We found that VNS significantly mitigated lung injury, as demonstrated by alleviation of pulmonary oedema and pathological alterations, by limiting inflammatory cytokine infiltration and increasing antioxidant capability. This proof-of-concept study suggested that VNS might protect patients from lung injury induced by hepatic I/R related to various circumstances.

Effect of sulphoraphane on newborn mouse cardiomyocytes undergoing ischaemia/reperfusion injury.

Context: Sulphoraphane (SFN) is an isothiocyanate, having antioxidant activity, antitumor, and therapeutic effects on cardiovascular disease.Objective: This study explores the mechanisms of SFN preconditioning on ischaemia/reperfusion injury (IRI).Materials and methods: Cardiomyocytes were divided into four groups as follows: control group (normoxic condition), SFN group (5 µmol/L), hypoxia/reoxygenation (H/R) group (1 h, 3 h) and SFN + H/R group. Cell viability was determined by MTT method. Levels of creatine kinase (CK), nitric oxide (NO), superoxide dismutase (SOD) and maleic dialdehyde (MDA) were determined by colorimetric method. Cell apoptosis, levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were determined by flow cytometry. Levels of Bax, Bcl-2, C caspase-3, NF-E2-related factor 2 (Nrf2) and haem oxygenase-1 (HO-1) were detected by Western blot.Results: H/R model inhibited cell viability, increased the levels of LDH, CK, Bax and C caspase-3, and decreased the levels of NO, Bcl-2, while the effect of H/R was partially reversed by SFN. SFN treatment reduced ROS, MDA (from 4.9 nM to 2.8 nM) production, elevated SOD level (from 39.5 U/mL to 61.7 U/mL) and improved MMP damage. Under the effect of SFN, up-regulation of nuclear Nrf2 expression and down-regulation of cytosolic Nrf2 expression were observed, which led to Nrf2 nuclear translocation and enhanced the expression of HO-1.Conclusion: These results suggested that SFN had a protective effect on cardiomyocytes undergoing IRI, and its mechanism may be realized via activating the Nrf2/HO-1 pathway, thereby inhibiting apoptosis. This might provide a new approach for the treatment of ischaemic heart disease.

Dihydromyricetin protects against lipopolysaccharide­induced cardiomyocyte injury through the toll­like receptor­4/nuclear factor­κB pathway.

Dihydromyricetin (DHM) is a bioactive flavonoid compound extracted from the stems and leaves of Ampelopsis grossedentata. Previous studies have indicated that DHM has antioxidation and antitumor capabilities, while the effect of DHM on lipopolysaccharide (LPS)­induced cardiomyocyte injury has not been clarified. Therefore, the aim of the present study was to investigate the effect of DHM on LPS­induced cardiomyocyte injury. In the present study, cardiomyocytes were randomized to the control (PBS), LPS and DHM + LPS groups. The LPS group was treated with 10 µg/ml LPS for 12 h and the DHM + LPS group was treated with 100 or 25 µM DHM 12 h prior to treatment with LPS. The protective effect of DHM on LPS­induced cardiomyocytes injury was evaluated by Cell Counting kit­8 assay, TUNEL staining, reverse transcription­quantitative polymerase chain reaction and western blot analysis. The results demonstrated that LPS treatment led to cardiomyocyte apoptosis, and these effects were significantly attenuated by DHM. Furthermore, LPS treatment downregulated the expression of B­cell lymphoma 2 apoptosis regulator (Bcl­2) and induced increased expression of Bcl­2­associated X apoptosis regulator (Bax). Additionally, DHM treatment reversed LPS­induced changes in Bcl­2 expression and Bax expression in cardiomyocytes, and rescued cells from apoptosis. In addition, increased mRNA expression levels of tumor necrosis factor­α and interleukin­6 induced by LPS were attenuated following treatment with DHM. Further investigation demonstrated that DHM suppressed the activation of toll­like receptor­4 (TLR4), which is involved in regulating the downstream signaling pathway of nuclear factor­κB (NF­κB). DHM attenuated LPS­induced cardiomyocyte injury, the potential mechanism responsible for this effect may involve inhibition of TLR4 activation and subsequent regulation of the associated downstream signaling pathway of NF­κB. The current study indicates that DHM may protect cardiomyocytes against LPS­induced injury by inhibition of the TLR4/NF­κB signaling pathway. The results of the present study may provide support for the development DHM as a strategy for the treatment of heart failure in septic shock.

[Role of NF-κB/survivin signal pathway on intima hyperplasia of rat carotid balloon injury restenosis model].

OBJECTIVE: To investigate the role of NF-κB/survivin signal pathway in the intima hyperplasia of rat carotid balloon injury restenosis model. METHODS: NF-κB siRNA lentivirus vector (titer was 1 × 108 TU/ml) was established. Carotid balloon injury restenosis model was made in 33 SD rats. The rats were divided into 4 groups according to different processing methods, including negative control (NC) group (n = 11), NF-κB siRNA group (n =11), NF-κB siRNA+YM155 (survivin inhibitor) (n = 11), the uninjured carotid artery served as the normal control group (n = 11). After 7 days, the carotid sample (n = 5 each group) were harvested to detect the NF-κB and survivin mRNA expression by RT-PCR.The carotid sample were harvested on 28 days (n = 6 each group) for HE staining and measuring intima hyperplasia. Immunohistochemical method was also used to detect the expression of intima proliferation cell nuclear antigen (PCNA) and media α-SM-actin. RESULTS: (1) After 7 days, NF-κB and survivin mRNA expression was significant higher in NC group than in normal control group (P<0.05), the NF-κB mRNA expression was significantly lower in NF-κB siRNA group than in NC group (P<0.05) and similar between NF-κB siRNA group and NF-κB siRNA+YM155 group. The survivin mRNA expression was significantly lower in NF-κB siRNA group compared to NC group (P<0.05) and significantly higher in NF-κB siRNA group than in NF-κB siRNA+YM155 group (P<0.05). (2) After 28 days, intima hyperplasia was observed in NC (0.13 ± 0.01), NF-κB siRNA (0.11 ± 0.01) and NF-κB siRNA+YM155 group (0.09 ± 0.01) mm² (P<0.05). Media area was similar among NC group, NF-κB siRNA group and NF-κB siRNA+YM155 group (P>0.05). I/M ratio was gradually reduced among NC group (1.55 ± 0.07), NF-κB siRNA group (0.92 ± 0.08), NF-κB siRNA+YM155 group (0.76 ± 0.06, all P<0.05). Similar results were found in the residual restenosis rate: NC group (58.71 ± 0.02) %, NF-κB siRNA group (32.13 ± 0.05) %, NF-κB siRNA+YM155 group (26.42 ± 0.03) % (all P<0.05) and expression of vascular smooth muscle cell PCNA: NC group (45.32 ± 7.21) %, NF-κB siRNA group (36.54 ± 6.42) %, NF-κB siRNA+YM155 group (28.57 ± 6.31) % (all P<0.05). On the contrary, the IOD of α-SM-actin in media increased gradually: NC group (0.055 ± 0.006), NF-κB siRNA group (0.072 ± 0.011), NF-κB siRNA+YM155 group (0.084 ± 0.008, all P<0.05). CONCLUSION: Inhibiting NF-κB expression can significant decrease intima hyperplasia in this model, and this effect may be mediated by inhibiting survivin and reducing the proliferation of vascular smooth muscle cells.