ABSTRACT
Objective:To investigate whether salidroside (SAL) improves lung tissue injury in rats with severe pneumonia (SP) through mediating toll-like receptor 4/nuclear transcription factor-κB/NOD-like receptor protein 3 (TLR4/NF-κB/NLRP3) signaling pathway.Methods:Seventy-five Wistar rats were used in this study. Fifteen of them were randomly selected as the sham operation group, and the others were induced by endotracheal infusion of Klebsiella pneumoniae ( Kp) suspension to construct a rat model of SP. After modeling, the rats were randomly divided into four groups with 15 rats in each group: model group, low-dose SAL group (30 mg/kg), high-dose SAL group (60 mg/kg) and dexamethasone (DXMS, 15 mg/kg) group. The sham operation group and the model group were given the same amount of normal saline for seven consecutive days. The wet-dry weight ratio (W/D) of lung tissues in each group was detected. HE and TUNEL staining methods were used to observe the morphology of lung tissues and cell apoptosis. The levels of TNF-α, IL-1β, IL-6, IL-18 and IL-10 in bronchoalveolar lavage fluid (BALF) were detected by ELISA. The expression of TLR4, myeloid differentiation factor (MyD88), NF-κBp65, phosphorylated NF-κBp65 (p-NF-κBp65) and NLRP3 at protein level in lung tissues was detected by Western blot. Results:The rat model of SP was successfully constructed by endotracheal infusion of Kp suspension. Compared with the sham operation group, the model group showed more severe edema of lung tissues, increased W/D value ( P<0.05), loose and incomplete alveolar structure, edema of alveolar wall and thickened alveolar wall, massive inflammatory cell infiltration, increased apoptosis rate as well as higher levels of TNF-α, IL-1β, IL-6 and IL-18 and lower lover of IL-10 in BALF. Moreover, the relative expression of TLR4, MyD88, NF-κBp65, p-NF-κBp65 and NLRP3 at protein level in lung tissues was increased in the model group ( P<0.05). Gradually improved pathological injury of lung tissues, decreased W/D value ( P<0.05), recovered alveolar structure, reduced alveolar wall edema and decreased cell apoptosis rate were observed in the low-dose and high-dose SAL groups as well as the DXMS group as compared with those of the model group. Besides, the three groups also showed decreased levels of TNF-α, IL-1β, IL-6 and IL-18 and increased level of IL-10 in BALF, and inhibited expression of TLR4, MyD88, NF-κBp65, p-NF-κBp65 and NLRP3 at protein level in lung tissues ( P<0.05). DXMS performed better in improving lung injury in rats with SP, followed by high and low doses of SAL ( P<0.05). Conclusions:SAL could reduce cell apoptosis and improve the Kp-induced lung injury in rats. The mechanism might be related to the blockage of TLR4/NF-κB/NLRP3 signaling pathway activation and inhibition of inflammatory factor expression.
ABSTRACT
Objective:To investigate the expression changes at the transcriptional level in normal lung tissues of mice after exposure to heavy ion radiation for different durations at different doses, aiming to provide evidence for exploring sensitive genes of heavy ion radiation, heavy ion radiation effect and the damage mechanism.Methods:Experiments on the temporal kinetics: the whole thorax of mice was irradiated with 14.5Gy carbon-ions and the total RNA of lung tissue was extracted at 3days, 7days, 3 weeks and 24 weeks. In dose-dependent experiment, the total RNA of lung tissue was extracted at 1 week after irradiated with a growing thoracic dose of 0, 7.5, 10.5, 12.5, 14.5, 17.5 and 20Gy. Protein-to-protein interaction (PPI) analysis and gene-ontology biological process enrichment analysis were performed on significant differentially expressed genes (DEGs).Results:A clearly differential expression patterns were observed at 3-day (acute stage), 1-week (subacute stage), 3-week (inflammatory stage) and 24-week (fibrosis stage) following 14.5Gy carbon-ions irradiation. Among those, the 3-day time point was found to be the mostly different from the other time points, whereas the 7-day time point had the highest uniformity with the other time points. Cellular apoptosis was the main type of cell death in normal lung tissues following carbon-ions exposure. The interactive genes of Phlda3, GDF15, Mgmt and Bax were identified as the radiosensitive genes, and Phlda3 was the center ( R=0.76, P<0.001). Conclusion:The findings in this study provide transcriptional insights into the biological mechanism underlying normal lung tissue toxicity induced by carbon-ions.
ABSTRACT
This study investigates the effect of the overexpression of the placental growth factor (PGF) and hyperoxia on lung development and determines whether anti-PGF antibody ameliorates hyperoxia-mediated impairment of lung development in newborn rats. After exposure to normoxic conditions for seven days, newborn rats subjected to normoxia were intraperitoneally or intratracheally injected with physiological saline, adenovirus-negative control (Ad-NC), or adenovirus-PGF (Ad-PGF) to create the Normoxia, Normoxia+Ad-NC, and Normoxia+Ad-PGF groups, respectively. Newborn rats subjected to hyperoxia were intraperitoneally injected with physiological saline or anti-PGF antibodies to create the Hyperoxia and Hyperoxia+anti-PGF groups, respectively. Our results revealed significant augmentation in the levels of PGF and its receptor Flt-1 in the lung tissues of newborn rats belonging to the Normoxia+Ad-PGF or Hyperoxia groups. PGF overexpression in these groups caused lung injury in newborn rats, while anti-PGF antibody treatment significantly cured the hyperoxia-induced lung injury. Moreover, PGF overexpression significantly increased TNF-α and Il-6 levels in the bronchoalveolar lavage (BAL) fluid of the Normoxia+Ad-PGF and Hyperoxia groups. However, their levels were significantly reduced in the BAL fluid of the Hyperoxia+anti-PGF group. Immunohistochemical analysis revealed that PGF overexpression and hyperoxia treatment significantly increased the expression of the angiogenesis marker, CD34. However, its expression was significantly decreased upon administration of anti-PGF antibodies (compared to the control group under hyperoxia). In conclusion, PGF overexpression impairs lung development in newborn rats while its inhibition using an anti-PGF antibody ameliorates the same. These results provided new insights for the clinical management of bronchopulmonary dysplasia in premature infants.