RESUMEN
Background: At present, bone union delay or failure remains challenging for clinicians. It has been reported that adipose-derived mesenchymal stem cells (ADMSCs) offer a promising way to promote bone fracture healing. In recent years, nanomaterials have been applied in regenerative medicine. This study aimed to investigate whether ADMSCs combined with platinum nanoparticles (PtNPs) could further improve fracture healing on the basis of ADMSCs. Methods: ADMSCs were co-cultured with PtNPs in vitro to investigate the effect of PtNPs on the differentiation of ADMSCs. Twenty Sprague-Dawley (SD) rats were randomly divided into four groups (with five rats in each group). The left tibias of all rats were fractured. Phosphate-buffered saline (PBS), PtNPs, ADMSC, and ADMSC mixed with PtNPs were then injected into the fracture sites based on the group classifications. The fracture was monitored by X-ray immediately after the fracture and on days 14 and 28 post-fracture. The tibias of the rats were subsequently harvested after the last X-ray and evaluated by micro computed tomography (micro-CT), histological analysis, and immunohistochemical detection. Results: PtNPs significantly enhanced the osteogenic differentiation of ADMSCs in vitro. On days 14 and 28 post-fracture, the radiographic score of the ADMSC + PtNPs group was higher than that of the ADMSC group, the score of the ADMSC group was higher than that of the PtNPs and control groups, and there was no significant difference between the PtNPs and control groups. Micro-CT confirmed that combined ADMSCs with PtNPs were more effective than using ADMSCs alone in promoting fracture healing. The histological and immunohistochemical results further supported this conclusion. Conclusions: Our findings demonstrated that PtNPs could promote osteogenic differentiation of ADMSC in vitro. ADMSCs combined with PtNPs could accelerate fracture healing further in vivo and are a promising a potential method for the treatment of fracture healing.
RESUMEN
Gaseous elemental mercury (GEM) is commonly known as a hazardous heavy metal in the atmosphere and is harmful to living organisms. GEM is chemically stable and has a long residence time in the atmosphere; hence, it can be transported over long distances with air masses and is regarded as a global pollutant. We study the transportation and transformation mechanisms of GEM and its potential anthropogenic and natural contribution sources. GEM, conventional atmospheric pollutants, and meteorological parameters were monitored at a coastal site in Ningbo during the summer and autumn of 2017. The results were as follows. â The concentrations of GEM ranged from 0.97-10.95 ng·m-3 and the mean and standard deviation (SD) were (2.32±0.90) ng·m-3, whereby the mean summer concentration was lower than the mean autumn concentration. â¡ The diurnal variations of GEM, ozone (O3), and gaseous oxidized mercury (GOM) during summer/autumn and sunny/rainy days suggest that higher levels of O3 and that strong solar radiation accounted for the rapid photochemical oxidation of GEM. The intensity of oxidation on sunny days was higher than that on rainy days. ⢠Correlation analysis showed that GEM was significantly positively correlated with PM2.5 (R=0.65, P<0.01), PM10 (R=0.47, P<0.01), NO2 (R=0.46, P<0.01), and CO (R=0.57, P<0.01). Local and regional sources of GEM were mainly related to fossil fuel combustion. ⣠The photochemical oxidation rate of GEM was influenced by the concentrations of oxidants (e.g., O3), gas-particle partitioning between GEM and particles, and light extinction effects of PM2.5, water vapor, and NO2. ⤠Potential source contribution analysis (PSCF) indicated that the northwestern Zhejiang Province (including Ningbo City), the southern Anhui Province, and most of Jiangxi Province constitute a triangular area that is a potential source contribution to NBUEORS atmospheric GEM pollution during the summer. Local, regional, and long-range sources all had strong impacts on GEM pollution. During the autumn, the potential sources were mainly in the northern Zhejiang Province, and the source was smaller than that during the summer. GEM pollution during the autumn was mainly influenced by local and regional sources. Therefore, the control of atmospheric GEM pollution in the Yangtze River delta should apply inter-regional prevention and comprehensive control strategies in order to reduce atmospheric mercury pollution.
