Cardiac mast cells accumulation and degranulation contribute to collagen deposition after coronary microembolization / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate potential pathophysiological role of cardiac mast cells accumulation and degranulation on the collagen deposition after coronary microembolization (CME).</p><p><b>METHODS</b>CME was induced in miniswine by selective infusion of 15X10(4) microspheres (diameter, 45 mum) into the left anterior descending artery groups (CME group, n=8). Some CME-induced animals were pretreated with the MC stabilizer tranilast (50 mg/kg, twice daily), beginning 2 weeks before CME and thereafter throughout the experimental period (CME +tranilast group, n=8), while some animals received tranilast without CME (tranilast group, n=8). Eight sham-operated animals without CME served as controls. After 30 days, the total number of MC and degranulating MCs and collagen deposition was assessed by histological and electronic microscopy studies.</p><p><b>RESULTS</b>The numbers of total and degranulating MCs and collagen volume fraction (CVF) at day 30 in CME group were significantly higher than those in controls (P <0.01). Treatment with tranilast significantly reduced the numbers of total and degranulating MCs and CVF at day 30 (all P <0.01). There was a significant positive correlation of the CVF with the number of total MCs (r=0.91, P <0.001) and degranulating MCs (r=0.92, P <0.001) over the CME myocardium.</p><p><b>CONCLUSION</b>MCs accumulation and degranulating contribute to myocardial fibrosis collagen deposition.</p>

Effects of RNA interference-induced tryptase down-regulation in P815 cells on IL-6 and TNF-alpha release of endothelial cells / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>To explore the effects of down-regulated tryptase expression in mast cells on the synthesis and release of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) of vascular endothelial cells.</p><p><b>METHODS</b>Tryptase-siRNA (small-interfering RNA) vector was constructed to inhibit tryptase expression in P815 cells. The medium of P815 cells treated by the tryptase-siRNA (RNAi-P815 group) or pure vector (P815 group) was collected and used to culture bEnd.3 cells. The messenger RNAs (mRNAs) of IL-6 and TNF-alpha in bEnd.3 cells and their protein levels in the medium were measured by reverse transcription polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively.</p><p><b>RESULTS</b>IL-6 and TNF-alpha mRNAs in bEnd.3 cells cultured in RNAi-P815-conditioned medium decreased significantly compared to those in P815-conditioned medium. Consistently, IL-6 and TNF-alpha protein levels in the medium of bEnd.3 of RNAi-P815 group were lower than those of P815 group.</p><p><b>CONCLUSION</b>Reduced tryptase expression significantly inhibited the synthesis and release of IL-6 and TNF-alpha in vascular endothelial cells. RNA interference targeting tryptase expression may be a new anti-inflammatory strategy for vascular diseases.</p>

Up regulation of interleukin-8 expressions induced by mast cell tryptase via protease activated receptor-2 in endothelial cell line / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Protease activated receptor-2 is cleaved and activated by trypsin or mast cell tryptase and may play an important role in inflammation. However, it is unknown whether PAR-2 can mediate tryptase-induced inflammatory reaction. This study was conduct to investigate whether PAR-2 could be the activated by mast cell tryptase and medicated the tryptase induced interleukin-8 expression in endothelial cells.</p><p><b>METHODS</b>Protease activated receptor-2 expression was found in endothelial cell lines ECV304 cell by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. Interleukin-8 stimulated by purified human mast cell tryptase was determined by RT-PCR and enzyme linked immunosorbent assay (ELISA). Data were analysed by the S-N-K one-way ANOVA test.</p><p><b>RESULTS</b>The present study shows that mRNA and protein of protease activated receptor-2 could be expressed in ECV304 cells, and tryptase upregulated the expression levels of both interleukin-8 mRNA and protein. The increased expression of interleukin-8 was inhibited by an antiprotease activated receptor-2 monoclonal antibody, SAM11. An additional band was observed by Western blotting after the incubation of ECV304 cells with tryptase for 2 hours, which suggested that protease activated receptor-2 was activated.</p><p><b>CONCLUSION</b>Protease activated receptor-2 can mediate the mast cell tryptase stimulated expression of interleukin-8 in ECV304 cell.</p>