Metformin alleviates chronic obstructive pulmonary disease and cigarette smoke extract-induced glucocorticoid resistance by activating the nuclear factor E2-related factor 2/heme oxygenase-1 signaling pathway

Chronic obstructive pulmonary disease (COPD) is an important healthcare problem worldwide. Often, glucocorticoid (GC) resistance develops during COPD treatment. As a classic hypoglycemic drug, metformin (MET) can be used as a treatment strategy for COPD due to its anti-inflammatory and antioxidant effects, but its specific mechanism of action is not known. We aimed to clarify the role of MET on COPD and cigarette smoke extract (CSE)-induced GC resistance. Through establishment of a COPD model in rats, we found that MET could improve lung function, reduce pathological injury, as well as reduce the level of inflammation and oxidative stress in COPD, and upregulate expression of nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), multidrug resistance protein 1 (MRP1), and histone deacetylase 2 (HDAC2). By establishing a model of GC resistance in human bronchial epithelial cells stimulated by CSE, we found that MET reduced secretion of interleukin-8, and could upregulate expression of Nrf2, HO-1, MRP1, and HDAC2. MET could also increase the inhibition of MRP1 efflux by MK571 significantly, and increase expression of HDAC2 mRNA and protein. In conclusion, MET may upregulate MRP1 expression by activating the Nrf2/HO-1 signaling pathway, and then regulate expression of HDAC2 protein to reduce GC resistance.

Huatanjiangqi capsule regulates Nrf2/HDAC2 and improves glucocorticoid resistance of 16HBE cells / 中国临床药理学与治疗学

AIM: To explore the effect of Huatanjiangqi capsule medicated serum (HTJQ) on the resistance of human bronchial epithelial cells (16HBE) to glucocorticoid (GC) stimulated by cigarette smoke extract (CSE). METHODS: After 16HBE cells were treated with HTJQ, the effects of different concentrations of HTJQ on the viability of 16HBE cells were determined by CCK-8 method. 16HBE cells were pretreated with HTJQ, and then cultured with dexamethasone (DEX) and lipopolysaccharide (LPS) for 24 hours, the effect of HTJQ on glucocorticoid (GC) resistance of 16HBE cells was determined by Enzyme-linked immunosorbent assay (ELISA). The effects of HTJQ, sulforaphane (SFN) and glutathione (GSH) on the expression of NF-E2-related factors 2 (Nrf2), Heme oxygenase-1 (HO-1) and histone deacetylase 2 (HDAC2) in 16HBE cells stimulated by CSE were measured by Western blot, and the effects of HTJQ, SFN and GSH on interleukin-8 (IL-8) in 16HBE cells were measured by ELISA. RESULTS: HTJQ promoted the proliferation of 16HBE cells at 1 h, 2 h and 4 h, the results of ELISA and Western blot showed that CSE induced GC resistance and decreased the expression of Nrf2, HO-1 and HDAC2 in 16HBE cells, HTJQ significantly decreased IL-8 and improved GC sensitivity of 16HBE cells (P<0.01), and up-regulated the expression of Nrf2, HO-1 and HDAC2 (P<0.01). In addition, HTJQ significantly up-regulated the level of GSH in 16HBE cells (P<0.01). Nrf2 agonists SFN and GSH significantly improved the glucocorticoid sensitivity of 16HBE cells (P<0.01), and up-regulated the expression of Nrf2, HO-1 and HDAC2 (P<0.01). CONCLUSION: HTJQ improves the GC resistance of 16HBE cells by up-regulating the expression of Nrf2/HDAC2 protein and the level of intracellular GSH.

Improved suture occlusion method to prepare focal cerebral ischemia reperfusion models in Sprague-Dawley rats / 中国组织工程研究

BACKGROUND:During the progress of focal cerebral ischemia-reperfusion in rat with transient suture occlusion, bleeding combating and the line being plugged into the cerebral middle artery smoothly are important for successful modeling and research focus. OBJECTIVE:To improve Longa suture occlusion method for focal cerebral ischemia reperfusion model in Sprague-Dawley rats in order to establish a simple surgical procedure with low rate of intraoperative bleeding and high rate of successful models. METHODS:The two ends of the external carotid artery were clipped with electric knife, in addition to ligation of surgery lines intraoperatively;with the help of pincett, a fishing line was plugged into the carotid artery along the anteriomedialis artery wal (the direction of the internal carotid artery from the pterygopalatine arterial bifurcation). Postoperative behavior scores in rats, infarct volume calculation and histopathological evaluation under optical microscope were done. RESULTS AND CONCLUSION:Transverse sections of the external carotid artery were changed from a“O” shape to a“-”shape after being clipped with electric knife. Subsequently, line nodes were not easy to fal off any more, effectively preventing intraoperative bleeding. With the power of pincett, the rate of plugging the fishing line into artery was significantly increased. Rat’s neurological score and infarct volumes were significantly increased, and brain tissue pathological injury worsened. The modified suture occlusion method for focal cerebral ischemia reperfusion models effectively prevented line nodes off, successful y increased the rate of suture occlusion and models in Sprague-Dawley rats were developed successful y.