Objective To observe the effect of bone marrow mesenchymal stem cells (BMSCs) conditioned medium on microglia (MGs) and its secretion of arginase 1 (Arg1). Methods The BMSCs separated through differential adhesion method from the femur and tibia marrow of 4-week-old Sprague Dawley (SD) rats were cultured and identified by Vimentin immunofluorescence staining; whereas MGs separated through trypsin digestion method from the brain of 3-day-old SD rats were cultured and identified by Iba1 immunofluorescence staining. The primary MGs were cultured with DMEM/F12 medium containing BMSCs conditioned medium (experimental group) and with single DMEM/F12 medium (control group), respectively. After 48 hours of culture, the morphology of MGs was observed by inverted phase contrast microscope, the activated state of MGs was detected by using Iba1 immunofluorescence staining, and Arg1 expression of MGs was assessed by Iba1-Arg1 double-labelling immunofluorescence staining and Western blot method. Results Inverted phase contrast microscope observation showed that BMSCs entered logarithmic growth phase at 14 days after culture, and more than 98% cells were positive to Vimentin immunofluorescence staining; whereas MGs entered logarithmic growth phase at 21 days after culture, and around 80% cells were positive to Iba1 immunofluorescence staining. Inverted phase contrast microscope observation displayed that in the experimental group, MGs were activated with increased size of soma, shortened process, and amoeba change. Immunofluorescence staining displayed that the Iba1 positive cells number in the experimental group was significantly higher than that in the control group (t=0.007, P=0.000); double-labelling immunofluorescence staining revealed that the Iba1-Arg1 positive cells number in the experimental group was significantly higher than that in the control group (t=0.007, P=0.000); and Western blot results elucidated that the relative expression of Arg1 protein in the experimental group was significantly higher than that in the control group (t=0.001, P=0.000). Conclusion BMSCs conditioned medium can activate MGs and induce MGs to express Arg1.
A great number of studies have demonstrated the structural and functional abnormalities in chronic schizophrenia (SZ) patients. However, few studies analyzed the differences between first-episode, drug-naive SZ (FESZ) patients and normal controls (NCs). In this study, we recruited 44 FESZ patients and 56 NCs, and acquired their multi-modal magnetic resonance imaging (MRI) data, including structural and resting-state functional MRI data. We calculated gray matter volume (GMV), regional homogeneity (ReHo), amplitude of low frequency fluctuation (ALFF), and degree centrality (DC) of 90 brain regions, basing on an automated anatomical labeling (AAL) atlas. We then applied these features into support vector machine (SVM) combined with recursive feature elimination (RFE) to discriminate FESZ patients from NCs. Our results showed that the classifier using the combination of ReHo and ALFF as input features achieved the best performance (an accuracy of 96.97%). Moreover, the most discriminative features for classification were predominantly located in the frontal lobe. Our findings may provide potential information for understanding the neuropathological mechanism of SZ and facilitate the development of biomarkers for computer-aided diagnosis of SZ patients.