Chronic psychological stress exacerbates aortic medial calcification via glucocorticoids / 生理学报

Chronic psychological stress can promote vascular diseases, such as hypertension and atherosclerosis. This study aims to explore the effects and mechanism of chronic psychological stress on aortic medial calcification (AMC). Rat arterial calcification model was established by nicotine gavage in combination with vitamin D3 (VitD3) intramuscular injection, and rat model of chronic psychological stress was induced by humid environment. Aortic calcification in rats was evaluated by using Alizarin red staining, aortic calcium content detection, and alkaline phosphatase (ALP) activity assay. The expression levels of the related proteins, including vascular smooth muscle cells (VSMCs) contractile phenotype marker SM22α, osteoblast-like phenotype marker RUNX2, and endoplasmic reticulum stress (ERS) markers (GRP78 and CHOP), were determined by Western blot. The results showed that chronic psychological stress alone induced AMC in rats, further aggravated AMC induced by nicotine in combination with VitD3, promoted the osteoblast-like phenotype transformation of VSMCs and aortic ERS activation, and significantly increased the plasma cortisol levels. The 11β-hydroxylase inhibitor metyrapone effectively reduced chronic psychological stress-induced plasma cortisol levels and ameliorated AMC and aortic ERS in chronic psychological stress model rats. Conversely, the glucocorticoid receptor agonist dexamethasone induced AMC, promoted AMC induced by nicotine combined with VitD3, and further activated aortic ERS. The above effects of dexamethasone could be inhibited by ERS inhibitor 4-phenylbutyrate. These results suggest that chronic psychological stress can lead to the occurrence and development of AMC by promoting glucocorticoid synthesis, which may provide new strategies and targets for the prevention and control of AMC.

[Progress on tendon-to-bone healing after rotator cuff repair].

Rotator cuff tear is a common disease that causes shoulder pain and limitation of activity. Rotator cuff repair with arthroscope has become the mainstream method with advance in surgical techniques. In spite of this, the highly rate of retear after surgery mainly because the tendon to bone interface form scar tissue rather than native tissue. Biomechanical of the interface is so poor to retear because of the change of Histological. In recent years, more and more researchers are devoted to the study of biology and biomechanical for improving the process of tendon to bone healing and restoring the original structure at the interface, This article reviews the research progress with four factors(inflammation, slow or limited bone ingrowth into the tendon graft, Mechanical stimulation, scant stem cell) and physiotherapy that affect tendon to bone healing.

Effects of paclitaxel on proliferation and apoptosis in human acute myeloid leukemia HL-60 cells.

AIM: To investigate the regulatory effect of paclitaxel on proliferation and apoptosis in human acute leukemia HL-60 cells. METHODS: HL-60 cell growth was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tertrazolium bromide (MTT) colorimetric assay. Cell cycle kinetics and apoptosis were analyzed by flow cytometry and microscopic examination. In addition, DNA microarrays containing 14,400 EST elements were used to investigate the gene expression pattern of HL-60 cells exposed to paclitaxel 1 micromol/L. RESULTS: Paclitaxel inhibited HL-60 cell growth significantly in a dose-dependent and time-dependent manner (P<0.01). Marked cell accumulation in G2/M phase and multinucleated cells were also observed after treatment with paclitaxel 0.1 and 1 micromol/L. Among 14400 EST elements, 277 genes were found to be markedly up- or down-expressed in the HL-60 cells treated with paclitaxel 1 micromol/L for 0.5 h, comprising 210 known genes and 67 unknown genes. CONCLUSION: Paclitaxel suppresses the growth of HL-60 cells in vitro by causing cell-cycle arrest and apoptosis. The results of microarray suggest that paclitaxel initiates apoptosis through multiple mechanisms.