ABSTRACT
BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) and BMSCs-derived exosomes have similar functions, but the regulatory mechanism underlying the release of exosomes is still unclear. OBJECTIVE: To investigate the role of GW4869, an inhibition of neutral sphingomyelinase 2, in the release of exosomes in BMSCs and the influence of GW4869 on BMSCs proliferation. METHODS: Rat BMSCs were divided into three groups: normal control group, 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (24-hour GW4869 treatment followed by 24-hour successive culture with drug withdrawal). Cultured cells were collected to extract exosomes by ultracentrifugation. Western blot was used to detect exosome-associated proteins CD63 and tumor susceptibility gene 101 (TSG101). The concentration and size distribution of exosomes were measured using nanoparticle tracking analysis. BCA was used to test the level of total proteins in exosomes. Live cell imaging system was used to observe the influence of GW4869 on BMSCs proliferation. RESULTS AND CONCLUSION: (1) Western blot results showed that exosomes expressed marker proteins such as CD63, TSG101. (2) Findings from the nanoparticle tracking analysis confirmed that the size of released exosomes was about 114 nm. (3) Significantly reduced release of exosomes was found in the two treatment groups compared with the normal control group (P < 0.01), but there was no significant difference between 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (P > 0.05). (4) No significant difference in the proliferation of BMSCs was found among the three groups (P > 0.05). To conclude, 24-hour W4869 can inhibit the release of exosomes by BMSCs and this inhibitory effect is still sustained within 24 hours after drug withdrawal. However, GW4869 has no influence on the proliferation of BMSCs.
ABSTRACT
Objective Acute lung injury induced by variety causes can be reduced by mesenchymal stem cells.Some studies have shown that mesenchymal stem cell-derived exosomes have similar features with mesenchymal stem cell,but its role in acute lung injury is less studied.The study was to investigate the protective role and underlying mechanisms of bone marrow mesenchymal stem cell-derived exosomes (BMSC-DEs) on smoke inhalation injury (SⅡ) in rats.Methods Thirty Wistar rats were randomly divided into 3 equal groups:normal control group,smoke inhalation injury (SⅡ) model group and bone marrow mesenchymal stem cell-derived exosomes (BMSC-DEs) treated group.12 h after establishing the SⅡ model,BMSC-DEs treated group was injected with 0.5 mL BMSC-DEs (derived from 4× 106 BMSCs),and normal control group and SⅡ model group were injected with equivalent volume of normal saline.7 days later,samples were collected.The histopathologic changes of lung were observed after HE staining;BCA was used to test the amounts of total protein in bronchoalveolar lavage fluid (BALF);Enzyme linked immunosorbent assay was used to test the levels of tumor necrosis factor-α (TNF-α) and keratinocyte growth factor (KGF) in the lung tissue;Immunohistochemical was used to test the levels of pulmonary surfactant protein C(SP-C).Results The BALF levels of total protein of SⅡ group was significantly higher than those of normal control group (P＜0.01) and BMSC-DEs groups(P＜0.05);Compared with normal group [(0.164±0.021) ng/L],the levels of tumor necrosis factor-α of SII and BMSC-DEs groups [(0.355±0.106)、(0.234±0.024) ng/L] (P＜ 0.05) were significantly higher,and SⅡ group was higher than that of BMSC-DEs group(P＜0.01);Compared with normal group,the KGF protein expression level in lung tissue of SⅡ group was significantly lower (P＜0.05),but BMSC-DEs group was higher (P＜0.05).BMSC-DEs group was higher than SⅡ group (P＜0.01);Immunohistochemistry showed that the SP-C expression level in lung tissue of SⅡ group was significantly lower than those of other groups (P＜0.05).There was no statistically difference between BMSC-DEs group and control group (P＞0.05).Conclusion BMSC-DEs has a protective effect of smoke inhalation injury rats,the underlying mechanism may be related to BMSC-DEs to reduce inflammation and promote restoration of the alveolar epithelial type Ⅱ.
ABSTRACT
BACKGROUND: Earthquakes, floods, droughts, storms, mudslides, landslides, and forest wild fires are serious threats to human lives and properties. The present study aimed to study the environmental characteristics and pathogenic traits, recapitulate experiences, and augment applications of medical reliefs in tropical regions. METHODS: Analysis was made on work and projects of emergency medical rescue, based on information and data collected from 3 emergency medical rescue missions of China International Search and Rescue Team to overseas earthquakes and tsunamis aftermaths in tropical disaster regions Indonesia-Aceh, Indonesia-Yogyakarta, and Haiti-Port au Prince. RESULTS: Shock, infection and heat stroke were frequently encountered in addition to outbreaks of infectious diseases, skin diseases, and diarrhea during post-disaster emergency medical rescue in tropical regions. CONCLUSIONS: High temperature, high humidity, and proliferation of microorganisms and parasites are the characteristics of tropical climate that impose strict requirements on the preparation of rescue work including selective team members suitable for a particular rescue mission and the provisioning of medical equipment and life support materials. The overseas rescue mission itself needs a scientific, efficient, simple workflow for providing efficient emergency medical assistance. Since shock and infection are major tasks in post-disaster treatment of severely injured victims in tropical regions, the prevention and diagnosis of hyperthermia, insect-borne infectious diseases, tropic skin diseases, infectious diarrhea, and pest harms of disaster victims and rescue team staff should be emphasized during the rescue operations.
ABSTRACT
Objective To study the effect of lipopolysaccharide(LPS)on the endo-pulmonary natrium channel(ENaC)expression in the lung of rats with acute lung injured.Method Sixteen rats were randomly divided into normal control group and LPS-group.Rats of normal control group and LPS-group were killed at 6 hours after intravenous injection of normal saline(8 ml/kg)or LPS(8 mg/kg).The extent of lung injury was assessed by arterial blood gas analysis and histological examination.At the same time,?-ENaC protein and???- ENaC mRNA expression in the lung tissue were analyzed by immunohistochemistry and RT-PCR.Results PaO_2 in LPS-group was noticeably lower than in normal control group(P