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6. Silk fibroin-hydroxyapatite scaffolds promote the proliferation of adipose-derived mesenchymal stem cells by activating the ERK signal.

Author

Xie, Xingqiao, Miao, Bianliang, Yao, Jinrong, and Chen, Zhongchun

Subjects
MESENCHYMAL stem cells, TISSUE scaffolds, CELL morphology, GENE expression, SILK fibroin, POLYMERASE chain reaction
Abstract

Adipose-derived mesenchymal stem cell (Ad-MSC) with capacities of releasing trophic factors and chondrogenic differentiation was a promising candidate for tracheal reconstruction. Silk fibroin (SF)- hydroxyapatite (HA) scaffolds were fabricated by the freeze-drying method. And Ad-MSCs were co-cultured on the scaffolds for 14 days in vitro. The role of the SF-HA scaffold in regulating the adhesion, growth, and proliferation of Ad-MSCs, and its potential mechanisms were investigated. The identity of Ad-MSCs was confirmed by cell morphology, surface markers, and differentiation characteristics. Cell proliferation, viability, and morphology were observed via CCK-8, live/dead assay, and scanning electron microscopy (SEM). Gene mRNA and protein levels were examined using quantitative real-time polymerase chain reaction and western blotting, respectively. SF-HA scaffolds showed excellent properties of promoting Ad-MSCs adhesion, growth, and proliferation for at least 14 days. In the CCK-8 assay, the relative OD value of Ad-MSCs cultured on SF-HA scaffolds increased (p < 0.001). Furthermore, live/dead staining showed that the fluorescent coverage increased with time (p < 0.05). SEM also showed that 3 days after inoculation, the coverage of Ad-MSCs on the SF-HA scaffolds was 78.15%, increased to 92.91% on day 7, and reached a peak of 94.38% on day 14. Extracellular signal-regulated kinase (ERK) mRNA and phosphorylated ERK (pERK) protein expression increased at day 3 (p < 0.05), followed by a significant decline at day 7 (p < 0.05). And ERK mRNA expression was positively correlated with Ad-MSCs proliferation (p < 0.05). In summary, the SF-HA scaffold co-cultured with Ad-MSCs is a promising biomaterial for tracheal repair by activating the ERK signal pathway. [ABSTRACT FROM AUTHOR]

Published
2023
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9. Transoral Endoscopic Localization of the Parapharyngeal Internal Carotid Artery.

Author

Zhang, Guoliang, Zhao, Xia, Sun, Guangbin, Gao, Nan, Yu, Pengcheng, and Chen, Zhongchun

Subjects
PHARYNGEAL muscles, SKULL base, INTERNAL carotid artery, LIGAMENTS, ANATOMY
Abstract

Objectives  To define transoral endoscopic surgical landmarks for the parapharyngeal segment of the internal carotid artery (ppICA) using cadaveric dissection. Methods  Ten fresh cadaveric heads were dissected to demonstrate the parapharyngeal space anatomy and course of the ppICA as seen in a transoral approach. Anatomical measurements of the distance between the ppICA and bony landmarks were recorded and analyzed. Results  The stylohyoid ligament, styloglossus, and stylopharyngeus could be considered to be the safe anterior boundary of the ppICA in the transoral approach; among them, the styloid ligament was the most rigid tissue. Dissection between the stylopharyngeus muscle and superior pharyngeal constrictor muscle provides direct access to the ppICA. At the level of the skull base, the distance from the root of the styloid process to the lateral margin of the external aperture of the carotid canal on the left side and on the right side was 8.57 ± 1.97 and 8.80 ± 1.21 mm, respectively. At the level of the maxillary tuberosity, the distance from the ppICA to the maxillary tuberosity on the left side and on the right side was 31.48 ± 2.24 and 31.01 ± 2.88 mm, respectively. Conclusion  The endoscopic-assisted transoral approach can facilitate exposure of the ppICA. The root of the styloid process, styloid ligament, and maxillary tuberosity are critical landmarks in the identification of the ppICA in the transoral approach. [ABSTRACT FROM AUTHOR]

Published
2022
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13. Efficacy of silk fibroin–nano silver against Staphylococcus aureus biofilms in a rabbit model of sinusitis

Author

Jia, Minghui, Chen, Zhongchun, Guo, Yongwei, Xin Chen, and Zhao, Xia

Subjects
Staphylococcus aureus, Silver, biomass, chronic rhinosinusitis, Administration, Topical, fungi, technology, industry, and agriculture, Maxillary Sinus, Staphylococcal Infections, Anti-Bacterial Agents, Nanocomposites, Catheters, Indwelling, Biofilms, Chronic Disease, Microscopy, Electron, Scanning, Animals, animal, Rabbits, Sinusitis, Fibroins, scanning electron microscopy, Original Research, nasal irrigation
Abstract

Background Staphylococcus aureus biofilms contribute significantly to the recalcitrant nature of chronic rhinosinusitis. In previous studies, it has been shown that silk fibroin–nano silver solution can eliminate S. aureus biofilms in vitro, which suggests a potential role of this novel agent in the treatment of biofilm-associated diseases, such as sinusitis. Objective The aim of this study was to investigate the efficacy of silk fibroin–nano silver solution as a topical anti-biofilm agent in a rabbit model of sinusitis. Methods Biofilm-associated sinusitis models were established in 24 New Zealand White rabbits by gelatin sponge placement and S. aureus inoculation through a hole drilled into the anterolateral wall of the right maxillary sinus. After 4 weeks, indwelling catheters were placed into the maxillary sinus. Different concentrations of silk fibroin–nano silver solution or normal saline were irrigated slowly into the maxillary sinus via the indwelling catheters. After 7 days of irrigation, the rabbits were sacrificed. The sinus mucosa was harvested and examined for biofilm biomass as well as morphological integrity of the epithelium by scanning electron microscopy. Results Silk fibroin–nano silver solution was found to be most effective in reducing the biomass of the S. aureus biofilms at a concentration of 384 mg/L, followed by the concentration of 153.6 mg/L, when compared with saline. After treatment with 384 mg/L silk fibroin–nano silver solution, the biofilms were completely eliminated and the injured epithelium was almost restored with regenerated cilia on the surface. Conclusion Silk fibroin–nano silver solution was found to be an effective topical agent against S. aureus biofilms in the rabbit model of sinusitis, and its effect was concentration-dependent.

Published
2017

15. A novel 3D-printed silk fibroin-based scaffold facilitates tracheal epithelium proliferation in vitro

Author

Zhong, Nongping, Dong, Tao, Chen, Zhongchun, Guo, Yongwei, Shao, Zhengzhong, Zhao, Xia, Zhong, Nongping, Dong, Tao, Chen, Zhongchun, Guo, Yongwei, Shao, Zhengzhong, and Zhao, Xia

Abstract

The functional epithelial regeneration is important for repairing tracheal defects. However, the potential of 3D-printed SF-based scaffolds for tracheal epithelial regeneration is still unknown. In this study, we developed a novel silk fibroin-based scaffold prepared by 3D printing of silk fibroin/hydroxypropyl methyl cellulose (SF/HPMC) thixotropic hydrogel and evaluated the tracheal epithelium proliferation on this scaffold in vitro. Combined with the freeze-dried technology, the 3D-printed SF/HPMC scaffolds had porous structures in the printed bars. After evaluation of their pore sizes, porosities, water contents and mechanical properties, the scaffolds were co-cultured with the normal human bronchial epithelial cell line (BEAS-2B) for seven days. We detected the BEAS-2B cells proliferation on the scaffolds using a CCK-8 assay, determined their mucin secretion and intercellular tight junction formation by immunofluorescence, as well as observed their cell viability and morphology by live/dead staining and scanning electronic microscopy. The results showed that the SF/HPMC scaffolds had good porosity, water content and mechanical properties. In addition, the BEAS-2B cells proliferated well on SF/HPMC scaffolds, during the seven-day co-culture, with high viability, mucin expression, and intercellular tight junction formation. In summary, these results demonstrated that the BEAS-2B cells could attach and proliferate on the 3D-printed SF/HPMC scaffolds, which were expected to have potential for facilitating tracheal epithelial regeneration.

Published
2019

21. Efficacy of silk fibroin–nano silver against Staphylococcus aureus biofilms in a rabbit model of sinusitis

Author

Jia,Minghui, Chen,Zhongchun, Guo,Yongwei, Chen,Xin, Zhao,Xia, Jia,Minghui, Chen,Zhongchun, Guo,Yongwei, Chen,Xin, and Zhao,Xia

Abstract

Minghui Jia,1,2 Zhongchun Chen,2 Yongwei Guo,2 Xin Chen,3 Xia Zhao2 1Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 2Department of Otolaryngology-Head and Neck Surgery, Huashan Hospital, Fudan University, 3State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials, Fudan University, Shanghai, China Background: Staphylococcus aureus biofilms contribute significantly to the recalcitrant nature of chronic rhinosinusitis. In previous studies, it has been shown that silk fibroin–nano silver solution can eliminate S. aureus biofilms in vitro, which suggests a potential role of this novel agent in the treatment of biofilm-associated diseases, such as sinusitis.Objective: The aim of this study was to investigate the efficacy of silk fibroin–nano silver solution as a topical anti-biofilm agent in a rabbit model of sinusitis.Methods: Biofilm-associated sinusitis models were established in 24 New Zealand White rabbits by gelatin sponge placement and S. aureus inoculation through a hole drilled into the anterolateral wall of the right maxillary sinus. After 4 weeks, indwelling catheters were placed into the maxillary sinus. Different concentrations of silk fibroin–nano silver solution or normal saline were irrigated slowly into the maxillary sinus via the indwelling catheters. After 7 days of irrigation, the rabbits were sacrificed. The sinus mucosa was harvested and examined for biofilm biomass as well as morphological integrity of the epithelium by scanning electron microscopy.Results: Silk fibroin–nano silver solution was found to be most effective in reducing the biomass of the S. aureus biofilms at a concentration of 384 mg/L, followed by the concentration of 153.6 mg/L, when compared with saline. After treatment with 384 mg/L silk fibroin–nano silver solution, the biofilms were c

Published
2017

24. Off-axis torsion tests on tubular specimens of steel

Author

Takeda, Takenobu and Chen, Zhongchun

Subjects
Mechanics -- Analysis, Sheet-steel -- Mechanical properties, Stress analysis (Engineering), Science and technology
Abstract

An off-axis torsion test by combined loading is developed to analyze the anisotropic hardening behavior of metals. The experiments have verified that anisotropy is more severe when a smaller offset strain is used in defining the yield stress.

Published
2001

35. Porous Three-Dimensional Silk Fibroin Scaffolds for Tracheal Epithelial Regeneration in Vitroand in Vivo

Author

Chen, Zhongchun, Zhong, Nongping, Wen, Jianchuan, Jia, Minghui, Guo, Yongwei, Shao, Zhengzhong, and Zhao, Xia

Abstract

The regeneration of functional epithelial lining is critical for artificial grafts to repair tracheal defects. Although silk fibroin (SF) scaffolds have been widely studied for biomedical application (e.g., artificial skin), its potential for tracheal substitute and epithelial regeneration is still unknown. In this study, we fabricated porous three-dimensional (3D) silk fibroin scaffolds and cocultured them with primary human tracheobronchial epithelial cells (HBECs) for 21 days in vitro. Examined by scanning electronic microscopy (SEM) and calcein-AM staining with inverted phase contrast microscopy, the SF scaffolds showed excellent properties of promoting cell growth and proliferation for at least 21 days with good viability. In vivo, the porous 3D SF scaffolds (n= 18) were applied to repair a rabbit anterior tracheal defect. In the control group (n= 18), rabbit autologous pedicled trachea wall without epithelium, an ideal tracheal substitute, was implanted in situ. Observing by endoscopy and computed tomography (CT) scan, the repaired airway segment showed no wall collapse, granuloma formation, or stenosis during an 8-week interval in both groups. SEM and histological examination confirmed the airway epithelial growth on the surface of porous SF scaffolds. Both the epithelium repair speed and the epithelial cell differentiation degree in the SF scaffold group were comparable to those in the control group. Neither severe inflammation nor excessive fibrosis occurred in both groups. In summary, the porous 3D SF scaffold is a promising biomaterial for tracheal repair by successfully supporting tracheal wall contour and promoting tracheal epithelial regeneration.

Published
2018
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