A 3D hydrogel loaded with exosomes derived from bone marrow stem cells promotes cartilage repair in rats by modulating immunological microenvironment / 南方医科大学学报

OBJECTIVE@#To assess the efficacy of GelMA hydrogel loaded with bone marrow stem cell-derived exosomes for repairing injured rat knee articular cartilage.@*METHODS@#The supernatant of cultured bone marrow stem cells was subjected to ultracentrifugation separate and extract the exosomes, which were characterized by transmission electron microscopy, particle size analysis and Western blotting of the surface markers. The changes in rheology and electron microscopic features of GelMA hydrogel were examined after loading the exosomes. We assessed exosome release from the hydrogel was detected by BCA protein detection method, and labeled the exosomes with PKH26 red fluorescent dye to observe their phagocytosis by RAW264.7 cells. The effects of the exosomes alone, unloaded hydrogel, and exosome-loaded hydrogel on the polarization of RAW264.7 cells were detected by q-PCR and immunofluorescence assay. We further tested the effect of the exosome-loaded hydrogel on cartilage repair in a Transwell co-culture cell model of RAW264.7 cells and chondrocytes in a rat model of knee cartilage injury using q-PCR and immunofluorescence assay and HE and Masson staining.@*RESULTS@#GelMA hydrogel loaded with exosomes significantly promoted M2-type polarization of RAW264.7 cells (P < 0.05). In the Transwell co-culture model, the exosome-loaded GelMA hydrogel significantly promoted the repair of injured chondrocytes by regulating RAW264.7 cell transformation from M1 to M2 (P < 0.05). HE and Masson staining showed that the exosome-loaded hydrogel obviously promoted cartilage repair in the rat models damage.@*CONCLUSION@#GelMA hydrogel loaded with bone marrow stem cell-derived exosomes can significantly promote the repair of cartilage damage in rats by improving the immune microenvironment.

Effect of Sodium Salicylate on Calcium Currents and Exocytosis in Cochlear Inner Hair Cells: Implications for Tinnitus Generation / 神经科学通报·英文版

Sodium salicylate is an anti-inflammatory medication with a side-effect of tinnitus. Here, we used mouse cochlear cultures to explore the effects of salicylate treatment on cochlear inner hair cells (IHCs). We found that IHCs showed significant damage after exposure to a high concentration of salicylate. Whole-cell patch clamp recordings showed that 1-5 mmol/L salicylate did not affect the exocytosis of IHCs, indicating that IHCs are not involved in tinnitus generation by enhancing their neuronal input. Instead, salicylate induced a larger peak amplitude, a more negative half-activation voltage, and a steeper slope factor of Ca2+ current. Using noise analysis of Ca2+ tail currents and qRT-PCR, we further found that salicylate increased the number of Ca2+ channels along with CaV1.3 expression. All these changes could act synergistically to enhance the Ca2+ influx into IHCs. Inhibition of intracellular Ca2+ overload significantly attenuated IHC death after 10 mmol/L salicylate treatment. These results implicate a cellular mechanism for tinnitus generation in the peripheral auditory system.

Establishment of an Embryonic Tip Regeneration System of Soybean

ABSTRACT In order to establish an optimal soybean embryonic tip regeneration system that can serve as soybean genetic transformation receptor, and be used for the study of genetic function verification, the influences of single factor on the adventitious bud of embryonic tip induction, elongation and rooting stage, are researched and compared.The single factors includes seeds soaking time, different kinds of hormones, different concentration of hormone and different concentration of sucrose. By one-way ANOVA and LSD ad hoc test , the results show that, for the embryonic tip adventitious bud induction stage, 12h is the optimal seeds soaking time, 2.0mg·L-1 is the optimal concentration of 6-Benzyl Aminopurine(6-BA), for the embryonic tip adventitious bud elongation stage, 0.2mg·L-1 indole-3-butyric acid (IBA) is optimal and 2.0mg·L-1Gibberellic acid (GA3) is optimal, and for the adventitious bud of embryonic tip rooting stage, 2.0mg·L-1 IBA is optimal,the average rooting rate is 93.34%. An Optimal embryonic tip regeneration system is established, and optimum mediums in different stages are found.