Electroacupuncture ameliorates blood-brain barrier disruption after ischemic stroke through histone acetylation regulation at the matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 2 genes.

OBJECTIVE: To explore whether the regulation of matrix metalloproteinase 9 (MMP-9)/ tissue inhibitors of MMPs (TIMPs) gene expression through histone acetylation is a possible mechanism by which electroacupuncture (EA) protects blood-brain barrier (BBB) integrity in a middle cerebral artery occlusion (MCAO) rat model. METHODS: Male Sprague-Dawley rats were divided into four groups: the sham group, the MCAO group, the MCAO + EA (MEA) group, and the MCAO + EA + HAT inhibitor (HATi) group. The MCAO model was generated by blocking the middle cerebral artery. EA was applied to Baihui (GV20). Samples were collected 1 or 3 d after reperfusion. Neurological function scores and Evans blue extravasation were employed to evaluate the poststroke injury. The effect of EA on MMP-9/TIMPs gene expression was assessed by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and chromatin immunoprecipitation (ChIP). RESULTS: Our results showed that EA treatment prominently improved neurological function and ameliorated BBB disruption. The RT-qPCR assay showed that EA reduced the expression of MMP-9 and promoted TIMP-2 mRNA expression, but HATi reversed these effects of EA. In addition, ChIP results revealed that EA decreased the enrichment of H3K9ace/H3K27ace at MMP-9 promoters and notably stimulated the recruitment of H3K9ace/H3K27ace at TIMP-2 promoter. CONCLUSION: EA treatment at Baihui (GV20) regulates the transcription of MMP-9 and TIMP-2 through histone acetylation modification in the acute stage of stroke, which preserves the structural integrity of the BBB in MCAO rats. These findings suggested that the histone acetylation-mediated transcriptional activity of target genes may be a crucial mechanism of EA treatment in stroke.

Cardioprotective effect of NRG-4 gene expression on spontaneous hypertension rats and its mechanism through mediating the activation of ErbB signaling pathway.

To explore the myocardial protective effect of Neuregulin-4 (NRG-4) gene expression on spontaneous hypertension (SHR) rats and its mechanism through mediating the activation of the ErbB signaling pathway, this study was conducted. For this purpose, forty 24-week-old male SPF SHR rats were selected as the experimental group, and 10 age and sex-matched Wistar Kyoto (WKY) rats were selected as the control group. Cardiac tissues were collected for hematoxylin-eosin (HE) staining, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining, Masson staining, and immunohistochemical staining. Following tail vein injection of recombinant lentiviral vectors, the experimental groups were constructed as the control group (SHR rats without any treatment), Empty vector group (Empty Vector transfection), shRNA negative control (NC) group (LV-shRNA-NRG-4 NC transfection to silence the expression of NRG-4), shRNA group (LV-shRNA-NRG-4 transfection), pcDNA3.1(-) NC group (pcDNA3.1(-)-NRG-4 empty vector transfection) and pcDNA3.1(-) group (pcDNA3.1(-)-NRG-4 transfection to overexpress NRG-4). Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to detect the expression levels In addition, methyl thiazolyl tetrazolium salt (MTT) assay and flow cytometry were performed to detect the proliferation and apoptosis of cardiomyocytes, respectively. Results showed that in the SHR group, the cardiomyocytes showed hypertrophy, disordered arrangement, hyperchromatic nucleus, irregular shape, obvious rupture of myocardial fibers, and obvious proliferation of fibrous stroma; obvious myocardial fibrosis, and there were more blue collagen fibers around cardiomyocytes and myocardial arterioles; cardiomyocytes were swollen, muscle fibers arranged disorderly, collagen around the coronary artery and myocardial interstitium increased significantly with a cross-linking appearance; besides, compared with WKY group, the apoptosis index of cardiomyocytes in SHR group was significantly increased (P<0.05). The expression of NRG-4 protein was decreased in the SHR group compared with the WKY group (P<0.05). In vitro, there was no difference in the mRNA expression of NRG-4, ErbB2 and ErbB4, MMP2, TGFß1 and α-SMA, as well as Caspase3, Bax and Bcl-2 among the control group, Empty vector group, shRNA NC group and pcDNA3.1(-) NC group (P>0.05). While shRNA group showed decreased expressions of NRG-4, ErbB2, ErbB4, MMP2, TGFß1, α-SMA and Bcl-2, while increased Caspase3 and Bax expressions, as well as promoted cell proliferation and cell apoptosis when compared with the shRNA NC group (P<0.05); while compared with pcDNA3.1(-) NC group, pcDNA3.1(-) group had highly increased expressions of NRG-4, ErbB2, ErbB4, MMP2, TGFß1, α-SMA and Bcl-2, while decreased Caspase3 and Bax expressions, inhibited cell proliferation and cell apoptosis (all P<0.05). It is concluded Upregulation of NRG-4 gene expression can promote the activation of the ErbB signaling pathway, thus inhibiting the proliferation and apoptosis of cardiomyocytes in SHR rats, reversing myocardial fibrosis, and playing its cardioprotective role.

Clinical characteristics of pneumonia patients of long course of illness infected with SARS-CoV-2.

Epidemiological and clinical characteristics of patients with COVID-19 have been reported in the last two years. A few studies reported clinical course of illness of median 22 days, including viral shedding of median 20 days, but there are several cases with a longer time of viral shedding. In this study, we included four cases with a longer illness course of more than 40 days who had been discharged or still in hospital by March 15, 2020. Demographic, clinical treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records. We described the epidemiological and clinical characteristics and the course of viral shedding. Two patients had comorbidity, one with hypertension and the other with diabetes. We found smoking was not an independent risk factor. D-dimer maybe related to the severity of illness but not to the course of the illness. Nucleic acid detection suggested that maybe more sampling sites represented more virus replication sites and longer course of illness. In this study we found some non-critical severe relatively young patients whose character was different from former studies described to provide a basis for reference to assess the risk of transmission and the isolation duration of patients.