The excessive reactive oxygen species (ROS) and hypoxia deteriorate the inflammation‐related diseases such as myocardial infarction (MI), and thereby deter the normal tissue repair and recovery and further lead to severe fibrosis and malfunction of tissues and organs. In particular, the MI has become one of the leading causes of death nowadays. In this study, a novel type of injectable hydrogel with dual functions of ROS scavenging and O2 generating is fabricated for MI treatment in vivo. The hydrogel is formed within 3 s from the synthetic ROS‐cleavable hyperbranched polymers and methacrylate hyaluronic acid (HA‐MA) under UV‐irradiation. Addition of biocompatible and applicable catalase in vivo enables the further transition of H2O2, a major type of ROS, to O2 and H2O. Results of rat MI model demonstrate that this hydrogel can significantly remove excessive ROS, inhibit cell apoptosis, increase M2/M1 macrophage ratio, promote angiogenesis, reduce infarcted area, and improve cardiac functions. With the appropriate degradation rate, simple structure and composition without cell seeding, and very excellent MI therapeutic effect, this ROS scavenging and O2 generating hydrogel has a great promise to be applied clinically.

Regeneration and functional recovery of peripheral nerves remain formidable due to the inefficient physical and chemical cues in the available nerve guidance conduits (NGCs). Introducing micropatterns and bioactive substances into the inner wall of NGCs can effectively regulate the behavior of Schwann cells, the elongation of axons, and the phenotype of macrophages, thereby aiding the regeneration of injured nerve. In this study, linear micropatterns with ridges and grooves of 3/3, 5/5, 10/10, and 30/30 μm were created on poly­(d,l-lactide-co-caprolactone) (PLCL) films following with surface aminolysis and electrostatic adsorption of graphene oxide (GO) nanosheets. The GO-modified micropatterns could significantly accelerate the collective migration of Schwann cells (SCs) and migration of SCs from their spheroids in vitro. Moreover, the SCs migrated directionally along the stripes with a fastest rate on the 3/3-GO film that had the largest cell adhesion force. The neurites of N2a cells were oriented along the micropatterns, and the macrophages tended to differentiate into the M2 type on the 3/3-GO film judged by the higher expression of Arg 1 and IL-10. The systematic histological and functional assessments of the regenerated nerves at 4 and 8 weeks post-surgery in vivo confirmed that the 3/3-GO NGCs had better performance to promote the nerve regeneration, and the CMAP, NCV, wet weight of gastrocnemius muscle, positive S100β and NF200 area percentages, and average myelinated axon diameter were more close to those of the autograft group at 8 weeks. This type of NGCs thus has a great potential for nerve regeneration.

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Chronic inflammation and remodeling of the bronchial wall are basic hallmarks of asthma. During the process of bronchial wall remodeling, inflammatory factors, such as transforming growth factor-β1 (TGF-β1), are known to induce the differentiation of fibroblasts into myofibroblasts, which leads to excessive synthesis and secretion of extracellular matrix (ECM) proteins, thus thickening and stiffening the basement membrane. However, it has not been thoroughly studied whether or not substrate stiffening affects the TGF-β1‑induced myofibroblast differentiation. In the present study, the influence of substrate stiffness on the process of bronchial fibroblast differentiation into myofibroblasts in the presence of TGF-β1 was investigated. To address this question, we synthesized polydimethylsiloxane (PDMS) substrates with varying degrees of stiffness (Young's modulus of 1, 10 and 50 kPa, respectively). We cultured bronchial fibroblasts on the substrates of varying stiffness in media containing TGF-β1 (10 ng/ml) to stimulate the differentiation of fibroblasts into myofibroblasts. Myofibroblast differentiation was examined using semi-quantitative RT-PCR for the expression of α-smooth muscle actin (α-SMA) mRNA and collagen I mRNA, the enzyme-linked immunosorbent assay method was used to assess the expression of collagen I protein and western blotting to assess the expression of α-SMA protein. The optical magnetic twisting cytometry (OMTC) method was used for the changing of cell mechanical properties. Our findings suggest that when fibroblasts were incubated with TGF-β1 (10 ng/ml) on substrate of varying stiffness, the differentiation of fibroblasts into myofibroblasts was enhanced by increasing substrate stiffness. Compared with those cultured on substrate with Young's modulus of 1 kPa, the mRNA and protein expression of collagen I and α-SMA of fibroblasts cultured on substrates with Young's modulus of 10 and 50 kPa were increased. Furthermore, with the increase of substrate stiffness, the cell stiffness and contractility were also increased, which also indicated further aggravation of asthma. This finding may help better understand the underlying mechanisms of hyperplasia of myofibroblasts in asthma, which has a marked significance in the therapy of asthma.

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