Silencing ApoC3 alleviates LPS-induced acute lung injury by inhibiting TLR signaling pathway.

This study aims to confirm whether apolipoprotein C3 (ApoC3) can regulate the inflammatory response and tissue damage in acute lung injury (ALI) and explore its regulatory pathway. ALI mouse model was established by intraperitoneal injection of lipopolysaccharide (LPS). ApoC3 levels were detected by real-time quantitative polymerase chain reaction, immunohistochemistry, and western blot assays. The levels of various inflammatory factors were detected by enzyme-linked immunosorbent assay and western blot analysis. Finally, the expression of toll-like receptor (TLR)/nuclear factor kappa B (NF-κB) signaling pathway-related protein [TLR2, myeloid differentiation primary response protein 88 (MyD88), IL-1 receptor-associated kinase 1 (IRAK1), NF-κB p65, and inhibitor of kappa B alpha (IκBα)], SLP adaptor and CSK interacting membrane protein (SCIMP), spleen tyrosine kinase (Syk), and phosphorylated (p)-Syk was detected by western blot analysis. ApoC3 was overexpressed in ALI mouse lung tissue and cell inflammation model. Silencing ApoC3 reduced inflammatory factors and alleviated lung tissue damage in ALI mice. Silencing ApoC3 reduced inflammatory factors and downregulated the expression of TLR2, MyD88, IRAK1, NF-κB p65, and increased IκBα expression in LPS-treated RAW264.7 cells. Moreover, co-transfection of si-TLR2 and shApoC3 further enhanced the inhibitory effects on the levels of inflammatory factors induced by silencing ApoC3. ApoC3 overexpression increased the levels of inflammatory factors and protein expression of SCIMP and p-Syk, while silencing TLR2 reversed the promotive effects of ApoC3 overexpression on above factors. In LPS-induced ALI mouse model and inflammatory cell model, downregulation of ApoC3 reduced inflammatory factors and relieved tissue damage. This process might be achieved through the TLR pathway.

Inhibition of microRNA-665 Alleviates Septic Acute Kidney Injury by Targeting Bcl-2.

Sepsis can easily cause acute kidney injury (AKI) and seriously endanger human health. This article aims to investigate and study the role of microRNA-665 (miR-665) in septic AKI and the underlying molecular mechanism. Lipopolysaccharide (LPS) was used to construct cell and animal models of septic AKI. The expression of miR-665 in cells and kidney tissues was detected by quantitative reverse-transcription polymerase chain reaction (RT-PCR). The contents of inflammatory factors (TNF-α, IL-1ß, and IL-6) in the cell supernatant were detected using commercial kits. Renal tissue damage was observed by hematoxylin-eosin (HE) staining. Kidney function was assessed by serum Cr, serum BUN, and urine NAG levels. The apoptosis of HK-2 cells was analyzed by flow cytometry and TUNEL staining. Luciferase activity assay was performed for the verification of the target of miR-665. The expression of miR-665 was increased in the cell model and animal model of septic AKI constructed by LPS. By transfecting miR-665 inhibitor in HK-2 cells and injecting miR-665 antagomir (antagomiR-665) through the tail vein of rats, the expression of miR-665 in HK-2 cells and rat kidneys was remarkably reduced. Silencing miR-665 dramatically inhibited the expression of inflammatory factors (TNF-α, IL-1ß, and IL-6) in LPS-induced HK-2 cells and reduced LPS-induced apoptosis in HK-2 cells. At the same time, the levels of serum Cr, serum BUN, and urine NAG decreased markedly, and the damage of the kidney was also alleviated. Finally, luciferase reporter experiments demonstrated that miR-665 directly targets Bcl-2. We revealed that miR-665 expression was increased in septic AKI, and silencing miR-665 could inhibit LPS-induced inflammation and apoptosis of the kidney by targeting Bcl-2, thereby improving renal function.

[Effects of exogenous hydrogen sulfide on intestinal function in rabbits after cardiopulmonary resuscitation].

OBJECTIVE: To investigate the effect of exogenous hydrogen sulfide (H2S) on intestinal mucosal barrier after cardiopulmonary resuscitation (CPR) in cardiac arrest (CA) rabbits. METHODS: Forty-four male New Zealand rabbits were divided into sham operation group (Sham group, n = 12), post-cardiac arrest syndrome (PCAS) group (n = 16) and H2S intervention group (PCAS+NaHS, n = 16) according to random number table method. The rabbit model of PCAS was established by tracheal clamping and suffocation, and CPR was started at 5 minutes after CA. However, Sham group did not clamp the tracheal intubation after anesthesia, and the other operations were the same as those in PCAS group. In the PCAS+NaHS group, a bolus of NaHS (0.5 mg/kg), a H2S donor, was injected via era vein 1 minute before the start of CPR, followed by a continuous injection of NaHS (1.5 mg×kg-1×h-1) for 3 hours, while the rabbits in other group were intravenously injected with the same volume of normal saline (NaCl 0.9%). Intestinal and portal vein blood samples were collected 24 hours after return of spontaneous circulation (ROSC). The level of serum fluorescein isothiocyanate-dextran (FD-4) was detected by fluorescein isothiocyanate (FITC) labeling method to reflect intestinal mucosal permeability. After hematoxylin-eosin (HE) staining of small intestine tissues, the morphological changes of mucosa were observed under light microscope, and the intestinal mucosa injury score was calculated. The expression of tight junction protein ZO-1 in intestinal mucosa was detected by immunohistochemistry. The content of malondialdehyde (MDA) in small intestinal tissue was determined by thiobarbituric acid chromogenic method, the activity of superoxide dismutase (SOD) was determined by xanthine oxidation method, and the level of myeloperoxidase (MPO) was determined by double antibody sandwich enzyme linked immunosorbent assay (ELISA) to reflect the oxidative stress and inflammatory reaction in small intestinal tissue. The expression of apoptosis protein (caspase-3) and autophagy related protein (Beclin-1, LC3) in small intestine tissue was detected by Western Blot. RESULTS: 12, 13 and 14 animals were successfully resuscitated in Sham group, PCAS group and PCAS+NaHS group respectively, while 12 animals in each group survived to the end of experiment. Compared with Sham group, the level of FD-4 in portal vein serum was significantly increased in PCAS group (mg/L: 11.95±0.59 vs. 1.43±0.48, P < 0.05), the pathological injury and inflammation infiltration were obviously aggravated under light microscope, the score of small intestine injury was significantly increased (4.21±0.37 vs. 0.36±0.18, P < 0.05), the expression of tight junction protein ZO-1 in the intestine was visibly down-regulated detected by immunohistochemistry, MDA content and MPO activity were significantly increased [MDA (nmol/mg): 3.65±0.32 vs. 1.54±0.24, MPO (U/g): 362±35 vs. 134±18, both P < 0.05], while SOD activity was significantly decreased (U/mg: 78.84±7.49 vs. 115.48±8.48, P < 0.05), the expression levels of cleaved capase-3, Beclin-1 and LC3 proteins in the intestine were significantly increased (caspase-3/ß-actin: 1.11±0.08 vs. 0.21±0.02, Beclin-1/ß-actin: 2.08±0.11 vs. 0.42±0.03, LC3/ß-actin: 1.05±0.07 vs. 0.37±0.05, LC3-II/LC3-I: 1.28±0.14 vs. 0.17±0.02, all P < 0.05). Compared with PCAS group, the portal vein serum FD-4 level in PCAS+NAHS group was significantly decreased (mg/L: 5.59±0.48 vs. 11.95±0.59, P < 0.05), the intestinal mucosal pathological injury and inflammatory cell infiltration were significantly decreased, the score of small intestine injury was significantly decreased (2.18±0.47 vs. 4.21±0.37, P < 0.05), the expression of ZO-1 in intestine was significantly increased, MDA content and MPO activity in intestine were significantly decreased [MDA (nmol/mg): 2.65±0.31 vs. 3.65±0.32, MPO (U/g): 251±21 vs. 362±35, both P < 0.05], while SOD activity was significantly increased (U/mg: 96.86±7.52 vs. 78.84±7.49, P < 0.05), while the expression of activated caspase-3, Beclin-1 and LC3 proteins was significantly decreased (caspase-3/ß-actin: 0.72±0.06 vs. 1.11±0.08, Beclin-1/ß-actin: 0.96±0.08 vs. 2.08±0.11, LC3/ß-actin: 0.72±0.06 vs. 1.05±0.07, LC3-II/LC3-I: 0.83±0.09 vs. 1.28±0.14, all P < 0.05). CONCLUSIONS: H2S has a protective effect on intestinal mucosal injury induced by CA/CPR, which may be related to tight junction protein ZO-1 up-regulation, oxidative stress alleviation, inflammation reduction, apoptosis and autophagy inhibition.