ABSTRACT
BACKGROUND:With the in-depth research of hydrogel materials,the applicable fields of hydrogel have been gradually broadened,and carrying stem cells for disease treatment has become a new direction of research,but how to construct a hydrogel suitable for stem cell growth is the key problem that needs to be solved at present. OBJECTIVE:To investigate the physicochemical properties of chitosan-chitosan biguanide hydrochloride-collagen composite hydrogels and to evaluate their ability to load mouse umbilical cord mesenchymal stem cells. METHODS:The hydrogels were prepared by physically cross-linking chitosan,chitosan biguanide hydrochloride and collagen with the cross-linking agents β-glycerophosphate sodium and sodium bicarbonate,and the suitable hydrogels were screened according to the gel formation time and gel formation effect(noted as Gel-1,Gel-2 and Gel-3 in this way).Morphology,porosity,swelling properties,and degradability of the three groups of hydrogels were observed by scanning electron microscopy.Hemolysis experiments were performed to examine the hemolysis of the three groups of hydrogels.The mouse umbilical cord mesenchymal stem cells were co-cultured with the hydrogel with the best comprehensive performance of characterization.The cytotoxicity,cell survival and adhesion effect of the composite hydrogel were determined to evaluate the performance of this hydrogel loaded with umbilical cord mesenchymal stem cells. RESULTS AND CONCLUSION:(1)Scanning electron microscopy characterization results showed that all three groups had porous mesh structures inside,and the internal structure of Gel-2 and Gel-3 with the addition of chitosan biguanide hydrochloride was more porous and three-dimensional.(2)The hydrogel porosity of the Gel-3 group was higher than the remaining two groups,with high porosity and uniform pore size distribution.(3)The swelling performance of all three groups of hydrogels was above 100%,and the swelling performance of hydrogels with chitosan biguanide hydrochloride component was better.(4)The degradation rate of the three groups of hydrogels could be degraded by more than 90%in a time scale of 15 days,with good degradation performance.(5)The results of the hemolytic properties showed that the absorbance values measured by each group of hydrogels carrying chicken erythrocytes were basically the same as those of saline carrying chicken erythrocytes,and no hemolysis occurred.(6)The toxicity experiment and living and dead cell staining showed that the survival rate of umbilical cord mesenchymal stem cells in each group of hydrogels was above 100%,indicating that there was no obvious cytotoxicity.Umbilical cord mesenchymal stem cells could survive under the hydrogel package and the hydrogels had a positive effect on the survival rate of umbilical cord mesenchymal stem cells.(7)The cells in the umbilical cord mesenchymal stem cell adhesion assay can survive under the hydrogel package and can adhere to the surface of the hydrogel with normal morphology.
ABSTRACT
With the global pandemic of COVID-19, cytokine storms in critical patients with pneumonia is really a problem and need to be solved immediately.Low dose radiation therapy (LDRT) has been temporarily used to treat pneumonia.In the past decades, researchers were dedicated to clarify the biological mechanism of LDRT.LDRT plays a unique role in the suppression of inflammation, preliminary outcomes have been acquired in critical patients with COVID-19 pneumonia, and radiotherapy community is paying attention to this treatment strategy.This review summarizes the application of LDRT in pneumonia, its biological mechanism, the result of LDRT in COVID-19 pneumonia, the existing problems and prospective in clinic.
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Objective To investigate the expression of nucleotide-binding oligomerization domain protein 2 (NOD2)in serum of patients with hepatocellular carcinoma (HCC),and to analyse the roles of NOD2 in HCC development and its clinical diagnostic value.Methods This study including 66 patients with HCC in the hospi-tal from March 1,2013 to December 31,2014 and 61 healthy controls.Serum NOD2 levels were determined by enzyme-linked immunosorbent assay (ELISA).Analysis of significance was performed with rank sum test using SPSS statistical 16.0 software.Results Serum levels of NOD2 in HCC patients were 171 pg/ml,significantly higher than that of healthy controls(95 pg/ml,Z =-5.00,P =0.00),and the serum NOD2 levels were correla-ted with clinical stage of HCC (H=56.26,P =0.00).Compared with the serum NOD2 levels in stageⅠ,Ⅱpatients (106 pg/ml)and healthy controls (95 pg/ml),the serum NOD2 level in stage Ⅲ and Ⅳ (220 pg/ml) were significantly increased (χ2 =31.24,P =0.00;χ2 =47.23,P =0.00),but the expression of NOD2 in stageⅠandⅡwere nearly equal to that of the healthy controls (χ2 =0.36,P =0.83).The ROC analysis revealed that the best diagnostic cutoff-point of serum NOD2 levels for predicting the Ⅲ and Ⅳ stages of HCC was 148.78 pg/ml,meanwhile corresponding sensitivity was 89.1% and specificity was 77.0%.Additionally,corre-lation analysis demonstrated that there was no significant correlation between NOD2 and alpha-fetal protein (r =0.44,P =0.14).Survival curves obtained that the survival time of HCC patients with NOD2 serum concentrations≥ 200 pg/ml was significantly less than that <200 pg/ml (χ2 =15.32,P <0.05).Conclusion NOD2 is highly expressed in the serum of HCC patients,especially in advanced patients,which is possibly involved in the development of HCC and has the potential to become an effective marker used for HCC diagnosis.