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OBJECTIVE To study the effects and potential mechanism of wogonin （Wog） on airway inflammation in rats with chronic obstructive pulmonary disease （COPD）. METHODS Eighty-four rats were randomly divided into control group， model group， Wog low-dose and high-dose groups （intragastric administration of 50， 100 mg/kg）， aminophylline group （positive control， intragastric administration of 2.3 mg/kg）， recombinant rat receptor-interacting protein kinase 1 [rRIPK1， receptor-interacting protein kinase 1 （RIPK1） activator] group （tail vein injection of 8 µg/kg）， and Wog high-dose+rRIPK1 group （intragastric administration of Wog 100 mg/kg+tail vein injection of rRIPK 8 µg/kg）， with 12 rats in each group. Except for control group， COPD model of other groups was induced by smoking combined with tracheal injection of lipopolysaccharide. Twenty-four hours after successful modeling， the rats were administered once a day for 4 weeks. The changes of peak inspiratory flow （PIF）， peak expiratory flow （PEF） and minute ventilation （MV），forced expiratory volume in one second（FEV1）/forced vital capacity（FVC） were measured after the last medication； the serum levels of interleukin 1β（IL-1β）， IL-6 and tumor necrosis factor-α （TNF-α） were measured by ELISA； the pathological changes of lung tissue in rats were observed； the apoptotic rate of pulmonary epithelial cells was detected. mRNA expressions of RIPK1， RIPK3 and mixed lineage kinase domain-like protein （MLKL）， and protein expressions of RIPK1， RIPK3 and p-MLKL were all detected in lung tissue of rats. RESULTS Compared with control group， PIF， PEF， MV and FEV1/FVC of model group were decreased significantly （P＜0.05）， while the levels of IL-1β， IL-6 and TNF- α were increased significantly （P＜0.05）； there was a large number of inflammatory cells infiltration in the lung tissue and bronchialwall thickening in model group； the apoptotic rate of pulmonary epithelial cells，mRNA expressions of RIPK1， RIPK3 and MLKL， protein expressions of RIPK1， RIPK3 and p-MLKL were increased significantly （P＜0.05）. Compared with model group， above indexes of rats were improved significantly in Wog low-dose and high-dose groups （P＜0.05）， and pathological injuries were alleviated significantly. The corresponding indexes of rats were worsened in rRIPK1 group （P＜0.05）， and pathological damage had further worsened. rRIPK1 significantly attenuated the inhibitory effect of high-dose Wog on airway inflammation and RIPK1/RIPK3/ MLKL pathway in COPD rats （P＜0.05）. CONCLUSIONS Wog may improve airway inflammation in COPD rats by inhibiting RIPK1/RIPK3/MLKL signal pathway.
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The morbidity of inflammatory bowel diseases (IBD) is rising rapidly but no curative therapies to prevent its recurrence. Cell death is crucial to maintaining homeostasis. Necroptosis is a newly identified programmed cell death and its roles played in IBD need to be explored. Necroptosis is mediated by receptor interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like protein (MLKL), which resulted in cell swelling, plasma membrane rupture, intracellular content leaking, and eventually cell death as well as the promotion of inflammation. Studies have found that inhibiting necroptosis alleviated IBD in animal models and IBD patients with an increased level of necroptosis in inflammatory tissues, indicating that necroptosis is related to the pathogenesis of IBD. However, due to the complexity in regulation of necroptosis and the involvement of multiple functions of relevant signaling molecules, the specific mechanism remains elusive. Necroptosis may play a vital regulatory role in the pathogenesis of IBD, which provides a new idea and method for further exploring the therapeutic target of IBD.
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Background Programmed necrosis is closely related to the occurrence and development of neurodegenerative diseases, but whether lead causes programmed cell necrosis has not been reported. Objective This experiment is designed to probe into the function of programmed necrosis and the effect of its inhibitor on lead-induced microglia (BV2 cell) injury. Methods The BV2 cells at logarithmic growth phase were treated with 0, 1, 5, 10, 25, 50, 100, and 200 μmol·L−1 lead acetate for 12, 24, 36, and 48 h, respectively, and methylthiazolyldiphenyl-tetrazolium bromide (MTT) was used to determine cell viability. After treatment with 0, 25, 50, and 100 μmol·L−1 lead acetate for 24 h, enzyme-linked immunosorbent assay, Western blotting, and flow cytometry were used to determine the expressions of tumor necrosis factor-α (TNF-α), receptor-interacting protein kinase 3 (RIPK3), receptor-interacting protein kinase 1 (RIPK1), and mixed lineage kinase domain-like protein (MLKL) in the cells, and the effect of RIPK1 inhibitor Nec-1 pretreatment on lead-induced BV2 cell injury . Results The BV2 cell viability decreased with higher lead concentration (r12 h=−0.995, r24 h=−0.984, r36 h=−0.983, r48 h=−0.981, all P<0.01) and time extension (only for 5 μmol·L−1 lead acetate, r=−0.994, P<0.01). Compared with the control group, the BV2 cell viability decreased at the same exposure time when the concentration of lead was above 10 μmol·L−1 (P<0.01). Compared with the control group, the expressions of RIPK1 and MLKL were increased in the 25, 50, and 100 μmol·L−1 lead groups (P<0.05 or 0.01), accompanied by an increase in the contents of inflammatory cytokine TNF-α, especially in the 100 μmol·L−1 lead group, the increment was the highest (P<0.01). The expression levels of p-RIPK1 and p-MLKL in BV2 cells were both increased when the concentration of lead acetate was above 50 μmol·L−1 (P<0.01). In addition, pretreatment with Nec-1 increased the cell viability rate and decreased the necrosis and late apoptosis rate of BV2 cells exposed to lead compared with corresponding lead exposure groups (P<0.05). Conclusions Lead can reduce BV2 cell viability, increase necrosis rate, and up-regulate the expressions of RIPK1, RIPK3, amd MLKL, and the phosphorylation levels of RIPK1 and MLKL. The RIPK1 inhibitor Nec-1 has an intervention effect on lead-induced damage in BV2 cells, indicating that programmed necrosis may play a role in lead neurotoxicity.
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Objective To explore the effects of bone marrow mesenchymal stem cells (MSCs) transplantation on receptor-interacting protein kinase 1 (RIP1) and RIP3 in rat brain after cardiac arrest (CA).Methods Sprague Dawley (SD) rats were randomly (random number) divided into sham group (n=8),CA group (n=8) and MSCs group (n=8).Animals were subjected to asphyxial cardiac arrest and followed by cardiopulmonary resuscitation (CPR).In MSCs group or CA group,animals received intravenous injection of 1 × 106 MSCs in 0.5 mL phosphate buffer solution (PBS) or 0.5 mL PBS alone at 1 h after successful resuscitation.Neurological deficit scores (NDS) were assessed at 3 d after CPR.Donor MSCs in brain were detected under a fluorescent microscope.HE staining of brain tissue was performed to observe necrotic neurons.Western blot analysis was performed to measure the levels of RIP1 and RIP3 in brain.Multiple comparisons were made by analysis of variance or Kruskal-Wallis H test.Results At 3 d after CPR,MSCs group demonstrated higher NDS than CA group [72.5(71.5,73.2) vs.63.0(62.5,64.1),Z=3.376,P=0.001].DAPI-labeled MSCs were primarily observed in the cerebral cortex.The percentage of necrotic neurons in MSCs group was significantly lower than that in CA group [(29.6±5.9)％ vs.(57.2±6.4)％,t=8.922,P＜0.01].The levels of RIP1 and RIP3 expression in brain in MSCs group were significantly lower than those in CA group [RIP1:0.227(0.193,0.243) vs.0.599(0.535,0.629),Z=3.151,P=0.001;RIP3:0.217(0.203,0.274) vs.0.543(0.533,0.555),Z=3.361,P=0.001].Conclusion MSCs transplantation improves neurological function after CPR from CA in rats likely associated with inhibiting necroptosis.