Beneficial effect of the mitochondrial ATP­sensitive potassium channel­specific opener nicorandil on the collapsed lung via inhibition of apoptosis in clinical thoracic surgery.

With the use of thoracoscopic surgery technology, one­lung ventilation (OLV) is becoming more crucial as a basic requirement for enhanced recovery after surgery; however, it can lead to severe pulmonary injury, which is an issue for anesthesiologists. Therefore, it is important to protect pulmonary function during thoracic surgery anesthesia, particularly to protect the function of the collapsed lung. Our previous study on rabbits reported that nicorandil, a US Food and Drug Administration­approved mitochondrial ATP­sensitive potassium channel­specific opener, can protect against lung injury in the collapsed lung. Therefore, the beneficial effect of nicorandil on OLV­induced pulmonary injury in clinical thoracic surgery was further evaluated in the present study. Nicorandil was infused at 2 mg/h for 2 h from induction to 1 h after OLV in the nicorandil group. Trends in arterial oxygen desaturation (SaO2), arterial partial pressure for oxygen (PaO2) and the lung microstructure were assessed. ELISA was used to assess the levels of TNF­α and malondialdehyde (MDA), and the activity of superoxide dismutase (SOD). A TUNEL assay was performed to evaluate apoptosis. Western blotting was used to analyze the relative expression levels of signaling proteins associated with apoptosis. Western blotting was performed to evaluate the protein expression levels of hypoxia­inducible factor 1α (HIF­1α), PI3K, Akt and NF­κB, and reverse transcription­quantitative PCR was used to detect HIF­1α mRNA expression levels in the lungs of patients infused with nicorandil and nitroglycerin. Nicorandil treatment was associated with higher SaO2 and PaO2 compared with nitroglycerin treatment in OLV. The levels of MDA and TNF­α in the operated lung of the nicorandil group were significantly lower compared with those in the control group. In addition, nicorandil was associated with higher SOD activity compared with nitroglycerin. The nicorandil­treated lung, similar to the sham group, exhibited improved microstructure and less apoptosis in the experimental group. The protein expression levels of PI3K, phosphorylated Akt and HIF­1α were significantly increased, whereas NF­κB was significantly decreased in the nicorandil­treated lung compared with the control group. Overall, nicorandil demonstrated beneficial effects by decreasing apoptosis in the operated lung, which was collapsed and then re­expanded during OLV in thoracic surgery anesthesia. Nicorandil may serve a vital role by decreasing the overloading of calcium in mitochondria, shutting off the mitochondrial membrane permeability transition pore, reducing the release of cytochrome c, simultaneously triggering activation of the PI3K/Akt signaling pathway around the cell membrane, downregulating NF­κB, upregulating HIF­1α, and then reducing Bax/Bcl­2, caspase­3 and apoptosis. The trial registration was ChiCTR­IOR­17014061 (registered on December 20, 2017).

Cannabinoid receptor agonist WIN55212-2 reduces unpredictable mild stress-induced depressive behavior of rats.

BACKGROUND: Depression is a neurological disorder characterized by persistent low mood. A number of studies have suggested that the use of type 1 cannabinoid receptor (CB1R) agonists can reduce depressive behavior, but its effect on the depressive behavior and nerve damage of rats exposed to chronic unpredictable mild stress (CUMS) has not been reported. METHODS: Rats were exposed to CUMS for 4 weeks to induce depressive behavior. Male Sprague-Dawley (SD) rats aged 6-8 weeks were randomly divided into six groups: control group (control), depression group (CUMS), depression + fluoxetine group (Flu), depression + WIN55212-2 group (WIN), depression + NF-κB inhibitor group (PDTC), and depression + WIN + PDTC group (WIN + PDTC). We performed four behavioral experiments test to evaluate the depressive behaviors of rats. Hematoxylin and eosin (HE) and Nissl staining were performed to observe the neuron structures of the hippocampus. Enzyme-linked immunosorbent assay (ELISA) was used to measure the concentrations of interleukin-1ß (IL-1ß), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2). Biochemical experiments were performed to evaluate the concentrations of nitric oxide (NO), malondialdehyde (MDA), reactive oxygen species (ROS), and superoxide dismutase (SOD). Fluorescence quantitative PCR was used to detect the mRNA expression of brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor B (TrkB), and inducible nitric oxide synthase (iNOS) in the hippocampus, and western blot was performed to detect protein expression levels related to the NF-κB signaling pathway in the hippocampus. RESULTS: Compared with the normal control group, CUMS significantly induced abnormal behaviors in stressed rats. The concentrations of pro-inflammatory factors and oxidative stress injury factors in the hippocampus of the CUMS group increased significantly. The interventions of Flu, WIN, and PDTC significantly reduced neuroinflammation and oxidative stress injury. Compared with the WIN group, the WIN + PDTC intervention group had better results. In addition, WIN could significantly inhibit the activation of the NF-κB signaling pathway. CONCLUSIONS: This study showed that cannabinoid receptor agonists can reduce the CUMS-induced depressive behaviors of rats by blocking the NF-κB signaling pathway to alleviate neuroinflammation and oxidative stress injury.