ObjectiveTo explore the antioxidant effects of reduced glutathione on rat pulmonary fibrosis compared with traditional corticosteroid.
MethodsOne-hundred and eight healthy SD rats were randomly divided into 6 groups,ie. a control group,a model group,a dexamethasone group,a low-dose glutathione group,a middle-dose glutathione group,and a high-dose glutathione group,with 18 rats in each group. The pulmonary fibrosis model was established by intratrachially instillation of bleomycin in all rats except the control group. The severity of lung fibrosis was evaluated by HE staining and Masson staining of collagen,and measurement of glutathione,hydroxyproline,superoxide dismutase (SOD),glutathion peroxidase (GSH-Px)in lung tissue homogenate by photocolorimetric method.
ResultsOn 7th day and 14th day after bleomycin instillation, the severity of alveolitis in the model group,the dexamethasone group,and three glutathione intervention groups was significantly reduced compared with the control group (P<0.05). On 28 day, the severity of lung fibrosis was significantly reduced in the dexamethasone group and three glutathione intervention groups compared with the model group (P<0.05). On 7th day,lung glutathione content was significantly lower in the model group compared with the control group (P<0.05), significantly higher in the dexamethasone group and three glutathione intervention groups compared with the model group (P<0.05), significantly lower in the dexamethasone group and the low-dose glutathione group compared with the control group (P<0.05), and significantly higher in the high-dose glutathione group compared with the dexamethasone group (P<0.05). On 7th,14th,and 28th day,the hydroxyproline content in the dexamethasone group and three glutathione intervention groups decreased significantly compared with the model group (P<0.05). On 14th day,the hydroxyproline content in the middle-dose and high-dose glutathione groups was significantly lower than that in the dexamethasone group (P<0.05). SOD and GSH-Px were significantly reduced in the model group compared with the control group on all time points (P<0.05),but significantly increased after intervention by different doses of glutathione (P<0.05).
ConclusionReduced glutathione can significantly reduce the degree of pulmonary fibrosis in rats,but has no obvious advantage over dexamethasone.
ObjectiveTo investigate the role of PI3K/Akt/HIF-1αsignaling pathway in bleomycin-induced pulmonary fibrosis in mice.
MethodsFifty-six C57BL/6 mice were randomly divided into a control group and a bleomycin (BLM) group.The pulmonary fibrosis model was induced by single intratracheal instillation of BLM(2.5 mg/kg) in the BLM group.Similarly, 0.9% saline was instilled directly into the trachea in the control group.Then all mice were sacrificed on 21st day.The lungs were collected for morphometric analysis with HE and Masson staining.The degree of pulmonary fibrosis was evaluated with Ashcroft score and content of hydroxyproline.The activity of PI3K/Akt/HIF-1αsignaling pathway and pro-surfactant protein C (Pro-SPC) were measured by Western blot.The level of collagen3 mRNA was assessed with quantitative real time PCR analysis.Collagen3 protein and numbers of apoptosis cells were observed with immuno-histochemistry.
ResultsIt was exhibited that the thickening alveolar septa, accumulation of inflammatory cells, and fibrous obliteration in the BLM group but not in the control group.There was a significant difference in Ashcroft score and hydryoproline content in the BLM group.Meanwhile, the activity of PI3K/Akt/HIF-1αsignaling pathway was up-regulated and the protein of Pro-SPC was decreased in the BLM group.It was revealed that the numbers of apoptosis cells, expressions of Collagen3 protein and mRNA were increased in the BLM group.
ConclusionAberrant activity of PI3K/Akt/HIF-1αsignaling pathway may aggravate the pulmonary fibrogenesis.
ObjectiveBy intervening with gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, to explore the downstream signaling pathway of the transcription factor forkhead box O3a (Foxo3a) in C57BL/6 mice who are induced to pulmonary fibrosis with bleomycin, as so to illuminate the possible mechanism of Foxo3a in epithelial-mesenchymal transition (EMT) of pulmonary fibrosis.MethodsThirty C57BL/6 mice aged 6 weeks in half genders were randomly divided into a control group, a bleomycin group and a gefitinib group. The mice in the control group were injected with saline via trachea. The mice in the bleomycin group were injected with bleomycin at a dose of 3 mg/kg via trachea. The mice in the gefitinib group were injected with bleomycin at a dose of 3 mg/kg via trachea and then gastrically perfused with gefitinib (20 mg·kg–1·d–1). 14 days after the treatment, all mice were killed and lung tissue specimens were collected for further detection. Lung tissue sections were stained with hematoxylin eosin and Masson’s trichrome. The mRNA levels of α-smooth muscle actin (α-SMA), E-cadherin, high mobility group protein box 1 (HMGB1), Foxo3a, FoxM1 and Snail1 in the lung tissues were detected by RT-PCR. The protein expressions of α-SMA, E-cadherin, HMGB1, phospho-Foxo3a (p-Foxo3a), Foxo3a, FoxM1 and Snail1 in the lung tissues were determined by western blot.ResultsThe scores of lung inflammation and fibrosis were evidently decreased in the gefitinib group compared with that in the bleomycin group (P<0.01). Compared with bleomycin group, the mRNA level of α-SMA, Snail1 (P<0.01) and HMGB1 (P<0.05) were declined, but mRNA level of E-cadherin (P<0.01), Foxo3a and FoxM1 (P>0.05) were ascendant in the gefitinib group. Meanwhile, western blot analysis showed reduced protein expressions of α-SMA (P<0.05), Snail1(P<0.01), HMGB1 (P<0.05) and p-Foxo3a/Foxo3a (P<0.01) in lung tissues, while expressions of E-cadherin (P<0.05), Foxo3a and FoxM1 proteins (P>0.05) were increased in the gefitinib group.ConclusionsIncreased activity of Foxo3a can down-regulate Snail1, which decreases the expression of α-SMA and increases the expression of E-cadherin, thereby attenuating bleomycin-induced pulmonary fibrosis in mice.
ObjectiveTo investigate the role of myeloid-derived suppressor cell (MDSC) in bleomycin (BLM)-induced pulmonary fibrosis and the possible mechanism of bone marrow mesenchymal stem cell (MSC) in therapy of BLM-induced pulmonary fibrosis.MethodsBone marrow mesenchymal stem cells (MSC) were harvested from 6-week old male BALB/c mice. One hundred and four female BALB/c mice were randomly divided into 3 groups. Mice in control (n=32) and BLM group were instilled with normal saline (NS) or BLM via trachea and NS were injected via tail vein on the 1st, 2nd and 3rd day after NS administration. Mice in MSC group (n=40) were instilled with BLM via trachea and MSC (total cell number=1.5×106) were injected via tail vein. On the 1st, 3rd, 5th, 8th, 11th, 14th, 18th, 21st, 25th and 32nd day after BLM administration, the percentage of Gr-1+CD11b+ cells in peripheral blood mononuclear cell (PBMC) was detected by flow cytometry. Eight mice from each group were killed on the 3rd, 8th, 18th and 32nd day after BLM administration, the percentage of Gr-1+CD11b+ cells in the lung tissue was detected by flow cytometry. Meanwhile, the lung tissue specimens were stained with Masson. The sry gene of Y chromosome was detected by polymerase chain reaction (PCR).ResultsCompared with BLM group, MSC transplantation significantly reduced pulmonary inflammation in MSC group [(1.32±0.25) vs. (2.53±0.56); and (1.06±0.42) vs. (2.27±0.82), respectively, P<0.01)]. Likewise, MSC transplantation significantly reduced pulmonary fibrosis and deposition of collagen as compared with BLM group [(1.02±0.44) vs. (1.81±0.74), and (1.51±0.73) vs. (2.72±0.54), respectively, P<0.05)]. The percentage of Gr-1+CD11b+ cells in the BLM group was significantly increased as compared with control group. Compared with BLM group, MSC transplantation significantly reduced Gr-1+CD11b+ cells in MSC group (P<0.05). The sry gene (201 bp) was detected in the lungs of female mice within 96 hours after MSC administration.ConclusionsMDSC participates in the procedure of BLM-induced pulmonary fibrosis. Syngeneic MSC inhibits the generation of MDSC and further suppresses BLM-induced pulmonary fibrosis.
ObjectiveTo investigate the therapeutic effect of kinetin on bleomycin A5 (BLM-A5)-induced pulmonary fibrosis in rats.
MethodsSixty female Wistar rats were randomly divided into three groups. Group A (n=20) was intratracheally injected with saline as control. Group B (n=20) were intratracheally injected with BLM-A5 to establish pulmonary fibrosis model. Group C (n=20) was intratracheally injected with BLM-A5 and received intraperitoneal injection of kinetin at 0.5 mL/100 g once daily. The rats were sacrificed on the 3rd,7th,14th and 28th day respectively. HE and Masson staining were performed to observe lung pathological changes. The contents of hydroxyproline (HYP),urokinase-type plasminogen activator (u-PA),tissue-type plasminogen activator (t-PA),and PAI-1 in lung and plasma were measured by ELISA.
ResultsAlveolitis was most obvious on the 7th day and pulmonary fibrosis was most severe on the 28th day in group B compared with other two groups (P<0.05). Alveolitis and pulmonary fibrosis in group C were significantly alleviated compared with group B (P<0.05),but still more severe than group A (P<0.05). The HYP contents in group B,coincided with fibrosis,began to increase on the 7th day and reached the peak on the 28th day,significantly higher than those in other two groups (P<0.05). The u-PA contents of lung tissue in group B began to decline on the 3rd day,reached the minimum on the 7th day,and was still significantly lower than those in other two groups (P<0.05).On the 14th day, the u-PA contents had no significant difference among three groups. The u-PA plasma contents in group B began to decline on the 3rd day,reached the minimum and had significant difference compared with other two groups on the 7th day (P<0.05),and there was no significantly difference among three groups after the 14th day. The t-PA contents change of lung tissue and plasma in three groups were generally consistent with u-PA,but the t-PA plasma contents in group B were still significantly lower than those in group A on the 14th day (P<0.05). The PAI-1 contents of lung tissue in group B began to increase on the 3rd day,reached the maximum on the 7th day,was still significantly higher than those in other two groups (P<0.05),and there was no significant difference among three groups on the 14th day. The PAI-1 contents in group C decreased compared with those in group B (P<0.05),but still higher than those in group A (P<0.05),and there was no difference among them on the 14th day. The PAI-1 plasma contents in group B began to increase on the 3rd day,reached the maximum and was significantly higher than other two groups on the 7th day (P<0.05),and there was no significant difference among three groups on the 14th day.
ConclusionThe contents of u-PA and t-PA are increased by inhibiting PAI-1 generation in lung tissue through kinetin treatment,so that,kinetin can suppress pulmonary fibrosis induced by BLM-A5.
ObjectiveTo investigate the effect of diammonium glycyrrhizinate (DG) plus bone marrow mesenchymal stem cells (MSCs) transplantation in the treatment of acute exacerbation of pulmonary fibrosis induced by bleomycin (BLM) in rats.MethodsMSCs were isolated from male Wistar rats and cultured in vitro. Twenty-four female Wistar rats were randomly divided into 4 groups. The NC group was intratracheally injected with normal saline; the BLM group, the MSC group and the DGMSC group were intratracheally injected with BLM for 7 days; then the MSC group was injected with 0.5 mL of MSCs solution (2.5×106 cells) into the tail vein; the DGMSC group was intraperitoneally injected with DG for 21 days in a dose of 150 mg·kg–1·d–1 on the base of the MSCs injection. The rats were sacrificed on the 28th day and the lung tissue was extracted. Pathological examination was performed to determine the degree of alveolitis and pulmonary fibrosis. Immunofluorescence was used to detect the number and distribution of alveolar type Ⅱ epithelial cells. Alkali hydrolysis method was used to determine the content of hydroxyproline (HYP) in lung tissue; thiobarbituric acid method was used to measure the content of malondialdehyde (MDA) in lung tissue; colorimetric method was used to determine the superoxide dismutase activity (SOD) and total antioxidant capacity (T-AOC); enzyme linked immunosorbent assay was used to detect the expression levels of tumor necrosis factor-α (TNF-α ) and transforming growth factor-β1 (TGF-β1) in lung tissue homogenates.ResultsThe DG combined with MSCs injection can reduce the degree of alveolitis and pulmonary fibrosis in BLM model rats. The content of HYP and TGF-β1 in lung tissue homogenate of the DGMSC group were significantly lower than those in the MSC group (P<0.05). Meanwhile, DG combined with MSCs injection significantly increased the antioxidant capacity of the BLM model rats. MDA content decreased, SOD activity and T-AOC ability improved significantly in the DGMSC group compared with the MSC group (P<0.05). The alveolar type Ⅱ epithelial cells were significantly increased and the cell morphology was maintained in the DGMSC group compared with the MSC group.ConclusionsDG has a synergistic effect with MSCs in treatment of acute exacerbation of pulmonary fibrosis. The mechanism may be related to reducing inflammatory factors during pulmonary fibrosis, attenuating oxidative stress and promoting MSCs migration into lung tissue and transformation to alveolar type Ⅱ epithelial cells.
Idiopathic pulmonary fibrosis (IPF) is a progressive scar-forming disease with a high mortality rate that has received widespread attention. Epithelial mesenchymal transition (EMT) is an important part of the pulmonary fibrosis process, and changes in the biomechanical properties of lung tissue have an important impact on it. In this paper, we summarize the changes in the biomechanical microenvironment of lung tissue in IPF-EMT in recent years, and provide a systematic review on the effects of alterations in the mechanical microenvironment in pulmonary fibrosis on the process of EMT, the effects of mechanical factors on the behavior of alveolar epithelial cells in EMT and the biomechanical signaling in EMT, in order to provide new references for the research on the prevention and treatment of IPF.
Objective To observe the effects of different doses of atorvastatin on bleomycin-induced pulmonary fibrosis in rats. Methods Seventy-five healthy female SD rats were randomly divided into five groups ( 15 rats in each group) , ie. a normal group , a model group, a 10 mg/ kg atorvastatin-treated group, a 20 mg/ kg atorvastatin-treated group, and a 40 mg/ kg atorvastatin-treated group. The rats in the model group and treatment groups were instilled with bleomycin in trachea( 5 mg/kg) , and the normal group were instilled with equal volume of normal saline. The treatment groups were gastric gavaged with different doses of atorvastatin each day from2 nd day on after instillation, and the normal group and model group were gavaged with normal saline. Blood samples were obtained from abdominal aorta in five rats in each group and blood gas analysis was performed on1st week, 2nd week and 4th week respectively after BLM instillation. Then the animals were killed and lung tissue samples were harvested for histopathology study. HE and Masson staining were used to determine the extent of alveolus inflammation and pulmonary fibrosis respectively.Histoimmunochemical stain were used to determine the protein levels of transforming growth factor-β1 ( TGF-β1 ) and connective tissue growth factor( CTGF) in pulmonary tissues. Results The arterial partial pressure of oxygenate ( PaO2 ) in the treatment groups were increased gradually with the increasing of therapeutic dose at each time point and decreased with prolongation of time in the same group. The protein levels of TGF-β1 and CTGF in pulmonary tissues were decreased gradually with prolongation of time. TGF-β1 and CTGF expressed obviously less in the treatment groups than those in the model group at each time point .The higher therapeutic doses were, the less the expressions of TGF-β1 and CTGF were. Conclusion Atorvastatin has remarkable inhibitory effects on BLM-induced pulmonary fibrosis of rats in a dose- and timedependentmanner.
ObjectiveThis study construct a pulmonary fibrosis model in vivo to study anti-pulmonary fibrosis effect of ampelopsis.MethodsWe constructed a pulmonary fibrosis model by bleomycin in BALB/c mice. The mice were divided by weight random number table into a blank control group, a model control group, a dexamethasone treatment group (intervened with dexamethasone in a dose of 2.5 mg/kg), and three ampelopsis treatment groups intervened with ampelopsis in dose of 200, 100, and 50 mg/kg, respectively. Bleomycin solution (3 mg/kg) was intratracheally injected respectively on 1st and 14th day, except the blank group. Twenty-eight days later, the relevant indicators were collected, including respiratory function (airway resistance, dynamic lung compliance, maximal ventilator volume), level of hydroxyproline and histopathological changes in the lungs.ResultsAfter 28 days, the model control group mice had severe respiratory resistance, dynamic lung compliance and maximal ventilator volume were decreased. The high dose ampelopsis treatment could enhance respiratory function (P<0.05). Lung coefficient was lower in the treatment groups than that in the model control group (P<0.05). The hydroxyproline of the treatment groups was less than that of the model control group (P<0.05). Histopathological examination showed that the degree of fibrosis increased in the model control group (P<0.05), but decreased in the treatment groups (P<0.05).ConclusionAmpelopsis can resist bleomycin-induced pulmonary fibrosis in mice, relieve the symptoms of respiratory failure, reduce the formation of collagen, and produce anti-pulmonary fibrosis effect.
Objective To study the pathology and possible mechanism of experimental hydrochloric acid（HCl） inhalation-indued pulmonary fibrosis in rats.Methods 120 male SD rats were randomly divided into a nomal control group，a bleomycin group，a high dose HCl group，a middle dose HCl group and a low dose HCl group.The bleomycin group was intratracheally injected with bleomycin once to induce pulmonary fibrosis.The three HCl groups were intratracheally injected with HCl once per week.The control group was given saline by the same way.Six rats of each group were randomly sacrificed on day 7，14，28 and 42 respectively.The histological changes of lung tissue were studied by HE and Masson’s trichrome staining.Hydroxyproline level in lung tissue was measured by digestion method.Protein and mRNA expression of transforming growth factor-β1（TGF-β1） were assayed by immunohistochemistry and RT-PCR respectively.Results Alveolitis in three HCl groups was significantl compared to control group，most severe at the second week，then remained at a high level which was equivalent to or exceeded the level of the bleomysin group after 28 days.Pulmonary fibrosis in three HCl groups was also significantly more severe than that in the control group，but milder than that in the bleomysin group.The high-dose and middle-dose HCl groups were not significantly different from the bleomysin group on day 42.There was no difference between three HCl groups in the earlier period，but the high-dose HCl group has a significantly difference from low-dose group on day 42.The content of hydroxyproline in high-dose and middle-dose HCl groups was also significantly higher than that in the control group.On day 42 hydroxyproline content in high-dose HCl dose rather middle –or low dose group was similiar with the level of bleomysin group.Content of TGF-β1 mRNA in three HCl groups was comparable to the level of bleomysin group on day 28 and exceeded on day 42.The expression of TGF-β1 in three HCl groups was not significantly different from the bleomysin group on day 42.Conclusion Experimental acid aspiration might contribute to pulmonary fibrosis in rats.Acid induced alveolar epithelial cell damage，abnormal proliferation and repair and fibrosis could be involved..
