Objective To explore whether epithelial to mesenchymal transition ( EMT) occurs in bleomycin( BLM) induced pulmonary fibrosis, and the involvement of bronchial epithelial cells( BECs) in the EMT. Methods BLM-induced peribronchial fibrosis in an α-smooth muscle actin-Cre transgenic mouse( α-SMACre /R26R) was examined by pulmonary βgal staining and α-SMA immunofluorescence staining. Results BLMtreated mice showed significantly enhanced βgal staining in subepithelial areas in bronchi, terminal bronchioles and walls of pulmonary vessels. Some alveolar epithelial cells( AECs) in certain peribronchial areas or even a small subset of BECs were also positively stained, as confirmed by α-SMA immunostaining. Conclusions EMT occurs in BLM-induced peribronchial fibrosis mice. BECs, like AECs, have the capacity to undergo EMT and to contribute to mesenchymal expansion in pulmonary fibrosis.
Objective To investigate the expression of high mobility group protein-B1( HMGB1)and α-smooth muscle actin( α-SMA) in Bleomycin induced pulmonary fibrosis in mice. Methods Twenty C57BL/ 6 male mice were randomly divided into a Bleomycin group and a control group. The Bleomycin group was treated with Bleomycin( 3 mg/kg) by endotracheally injection to induce pulmonary fibrosis. The control group were treated with normal saline( NS) . Then they were sacrificed by abdominal aortic bleeding 10 days after the injection. The right lung was stained with hematoxylin-eosin and Masson trichrome respectively for pathological examination. Immunohistochemistry and RT-PCR were performed to identify the protein and mRNA levels of α-SMA and HMGB1 respectively. Results The mRNA( 0. 89 ±0. 12, 0. 61 ±0. 08) and protein( 13. 66 ±1. 01, 13. 12 ±1. 33) expressions of α-SMA and HMGB1 in the Bleomycin group were all significantly higher than those of the control group( mRNA: 0. 60 ±0. 07, 0. 15 ±0. 02; protein: 8. 18 ±1. 33,7. 92 ±1. 10; all P lt; 0. 01) . Conclusions The expressions of HMGB1 and α-SMA are increased in Bleomycin induced pulmonary fibrosis. HMGB1 participates in the pathological process of pulmonary fibrosis probably by activation of the α-SMA expression.
ObjectiveTo investigate the mechanism of impeded wound healing by exogenous hyaluronan (HA). Methods Wound healing models were established on 18 adult rabbit ears, which were randomly divided into 3 groups, the 2% HA treated-group (group A), the 1% HA treated-group(group B), and the PBS control-group (group C). The process of wound healing was observed morphologically and histologically. The expression of α-smooth muscle actin in fibroblast was measured by immunohistochemical method. Results ①The mean values of wound healing time of groups A, B and C were (11.7±0.6), (11.3±0.6), and (10.8±1.0) days respectively. Wound contraction was greater in group C than in group A and group B. ②Compared with PBS controls, the collagen fibril was slender and arrayed regularly in HA treated wound. ③ The expression of α-smooth muscle actin was greater in group C than in groups A and B. Conclusion It is one of reasons of impeded wound healing that exogenous HA inhibits the expression of α-smooth muscle protein and wound contraction. There exists dose-dependant effect.
OBJECTIVE: To explore the expression of alpha-smooth muscle actin (alpha-SMA) induced by transforming growth factor beta 1 (TGF-beta 1). METHODS: Five samples of hypertrophic scars and three samples of normal mature scars were collected as the experimental and control groups respectively. The fibroblasts were isolated from scars, and cultured in 2-dimension or 3-dimension culture system. The immunohistochemical staining method of LSAB were used to investigate the expression of alpha-SMA in fibroblasts in the different concentration of TGF-beta 1. RESULTS: The expression of alpha-SMA in 3-dimension culture system were markedly lower than those in 2-dimension culture system with respect to the fibroblasts in the experimental group. The expression of alpha-SMA in fibroblasts were different in response to various TGF-beta 1 concentration, it was more effective at the concentration of 5 ng/ml. The expression of alpha-SMA in the fibroblasts from hypertrophic scars seemed to be more sensitive to TGF-beta 1 compared to that of the normal mature scars. CONCLUSION: There are concentration-dependent in the expression of alpha-SMA induced by TGF-beta 1 in scar fibroblasts in vitro. The biological characteristics of the fibroblasts from hypertrophic scars and normal mature scars and their sensitivity to the inducement of TGF-beta 1 were different. The inducement of TGF-beta 1 may be depressed by extracellular matrix components and that may decrease the expression of alpha-SMA.
Objective To investigate the expression of vascular endothelial growth factor-A （VEGF-A） and the phenotypic transition after the activation of fibroblasts by the supernatant of cultured tumor cells．Methods The growth tendency of fibroblasts was tested by the MTT assay．The expressions of alpha-smooth muscle actin （α-SMA） and VEGF-A mRNA were tested by RT-PCR．The expressions of α-SMA and VEGF-A protein were tested by immunohistochemistry and Western blot．Results The MTT assay indicated that the conditional medium which contained tumor cells supernatant could obviously promote the growth of the fibroblasts． RT-PCR and Western blot manifested that α-SMA expressed by the fibroblasts which cultured by normal medium reached its peak on day 5，then decreased to a low level on day 7．When the medium contained 2 ng/ml transforming growth factor-β1 （TGF-β1），the fibroblasts could steadily express more α-SMA．But the above two mediums could not make the fibroblasts express the VEGF-A. When using the conditional medium，the α-SMA peak advanced on the third day and maintained at a high level，so as the expression of the VEGF-A．Conclusions The results suggested that fibroblasts can be activated to be myofibroblasts when using the conditional medium．The best activation time of the fibroblasts is consistent with the time of the VEGF-A expression at the highest level by the activated fibroblasts．The fibroblasts which activated at the best time are expected to become a kind of cells which can be used for promoting revascularization．
Objective To validate the mechanism of effect of hepatic artery ischemia on biliary fibrosis after liver transplantation and the prevention method. Methods Eighteen male dogs were established into the concise auto orthotopic liver transplantation models and assigned into three groups randomly: hepatic artery ischemia (HAI) group, TBB group (transferred the blood by a bridge duct ) and control group, each group contained 6 dogs. After opening portal vein, the samples were cut from liver in each group at the time of 6 h, 3 d and 14 d. The pathological modifications of intrahepatic bile ducts were observed and expression of transforming growth factor-β1 (TGF-β1) were detected in the three times. Expressions of Smad3 and phosphate-Smad3 as well as mRNA of α-smooth muscle actin (α-SMA) in intrahepatic bile ducts were detected 14 d after opening portal vein.Results Compared with control group, the collagen deposition and lumens stenosis in biliary vessel wall were more obviously in HAI group. In TBB group, the pathological modifications were slighter compared with HAI group. The positive cell index of TGF-β1 reached peak on day 3 after opening portal vein, then decreased in TBB group, and which in HAI group kept increase and was significantly higher than that in TBB group （Plt;0.05）. The expression level of phosphate-Smad3 and transcriptional level of α-SMA mRNA were 1.04±0.13 and 1.12±0.55 in TBB group on day 14 after opening portal vein, which were significantly higher than those in control group (0.59±0.09 and 0.46±0.18) and lower than those in HAI group (1.82±0.18 and 1.86±0.73), the diversities among three groups were significant (Plt;0.05). There was not significant difference of expression of Smads among three groups (Pgt;0.05). Conclusions Hepatic artery ischemia could increase the deposition of collagen fibers and the transdifferentiation of myofibroblast in bile duct and result in the biliary fibrosis by activating the TGF-β1/Smads signaling pathway. The bridging bypass device could lessen the biliary fibrosis caused by hepatic artery ischemia by inhibiting the activation of TGF-β1/Smads signal transduction passageway.