Preparation and in vitro Evaluation of Injectable Alginate/Thiolated Chitosan Hydrogel Scaffold for Neural Tissue Engineering

Introduction: Spinal cord injuries are one of the main causes of disability with devastating neurological consequences and secondary conflicts in other organs. Tissue engineering and regenerative medicine have been recognized as novel, promising methods in the treatment of tissue injuries, especially in neurological damage in recent decades. Hydrogels have the advantage of compatibility with damaged tissue, and injectable hydrogels can be applied in minimally invasive surgeries. This study aimed to evaluate an injectable hydrogel-based scaffold consisting of thiolated chitosan and alginate for neural tissue regeneration. Materials and Methods: In the present study, an injectable hydrogel-based containing thiolated chitosan and alginate was prepared. Microbiology and pH tests were performed. Microstructural properties and porosity of scaffold were evaluated by scanning electron microscope (SEM). The swelling /shrinkage ratio and rates of biodegradation were also conducted. Finally, the viability of L929 cells on the scaffold was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: Thiolated chitosan/ alginate hydrogel had low pH with no contamination. SEM showed hydrogel had a porous microstructure with a mean pore diameter of 21.89 ± 0.32 μm which is suitable for cell culture. Furthermore, according to MTT test results, this hydrogel was biocompatible. Conclusion: Thiolated chitosan/ alginate hydrogel is convenient for application in neural tissue engineering based on its structural properties and its ability to support cell proliferation. According to the in vitro analysis, it can also be used as a scaffold to create a suitable environment for increasing cell viability

Intrapulmonary autologous transplant of bone marrow-derived mesenchymal stromal cells improves lipopolysaccharide-induced acute respiratory distress syndrome in rabbit

Abstract Background Lung diseases such as acute respiratory distress syndrome (ARDS) have a high incidence worldwide. The current drug therapies for ARDS have supportive effects, making them inefficient. New methods such as stromal cell therapy are needed for this problem. Methods This research was performed with ten New Zealand rabbits in two groups. Bone marrow aspiration was performed on the treated group, and mesenchymal stem cells were isolated and cultured. The experimental model of ARDS was induced using LPS from Escherichia coli strain O55:B5. Then, 1010 bone marrow mesenchymal stem cells (BM-MSCs) were autologously transplanted intrapulmonary in the treatment group, and 1–2 ml of PBS in the control group. The clinical signs, computed tomographic (CT) scans, echocardiography, blood gas analysis, complete blood count, and cytokine levels were measured before and at 3, 6, 12, 24, 48, 72, and 168 h after BM-MSC transplant. Finally, the rabbits were killed, and histopathological examination was performed. Results The results showed that BM-MSCs decreased the severity of clinical symptoms, the number of white blood cells and heterophils in the blood, the total cell count, and number of heterophils and macrophages in bronchoalveolar lavage, and balanced the values of arterial blood gases (increase in partial pressure of oxygen and O2 saturation and decrease in the partial pressure of carbon dioxide). They also downregulated the tumor necrosis factor (TNF)-α and interleukin (IL)-6 concentrations and increased the IL-10 concentrations at different times compared with time 0 and in the control group, significantly. In the CT scan, a significant decrease in the Hounsfield units and total lung volume was found by echocardiography, and in comparing the two groups, a significant difference in the parameters was noticed. The histopathology demonstrated that the BM-MSCs were able to reduce the infiltration of inflammatory cells and pulmonary hemorrhage and edema. Conclusions This study indicated that BM-MSCs play a significant role in the repair of lung injury