Effect Of U73122, A Phospholipase C Antagonist, On Accumlation Of CD8+ T Lymphocyte And Expression Of MMP-9,MMP-12 In Rats With COPD

ObjectiveTo investigate the effect of U73122,a phospholipase C antagonist, on accumulation of CD8+ T cell and expression of MMP9 and MMP12 in rats with COPD and revealed the role of CD8 + T cells in the pathogenesis of COPD.MethodsEighty gradeⅡmale Wistar rats, two months old and initially weighing (200±10)g , were divided into three groups : nomal control group,COPD model group and treatment group. 20 rats in nomal control group were maintained under normal condition for 12 weeks. 20 rats in the COPD model group(CS group) and 40 rats in the treatment group were injected with 200ug lipopolysaccharide (Sigma, USA) intratracheally once every six weeks (twice),and exposed to 5% smoke for 0.5h/d for 12 weeks. The smoke exposure box was 60 cm×40 cm×30 cm.In the treatment group,20 rats were treated with U73122(CS+U73122 group) and the other were treated with U73343 as negative control(CS+U73343 group). U73122 and U73343(9mg/kg,Cayman Chemical,USA) were injected into the caudal veins of rats once every day,lasting 12 weeks.Lymphocytes, macrophages, and neutrophil of bronchoalveolar lavage fluid (BALF) were counted and proportion of CD8+T lymphocyte was detected by Flow Cytometric Analysis. Interferon-gamma (IFN-γ) levels in BALF and lung tissue samples were determined by Enzyme Linked Immunosorbent Assay (ELISA). The expression of PLC, CXCL10, and CXCL11 in lung tissue was determined by real-time reverse transcriptase–polymerase chain reaction (RT-PCR). The levels of MMP-9 and MMP-12 were determined by western blot analysis and the morphological changes in MAN and LM of lungs were observed. ResultsIn comparison with the control group , rats in COPD model group had a significant increase in CD8+T cell accumulation ,expression of MMP9,MMP12,PLCmRNA,CXCL10mRNA,CXCL11mRNA and IFN-γlevels. After treatment with U73122, compared to COPD model group,the parameters above were decreased.Additionally, the morphological changes were also improved.ConclusionsPhospholipase C-mediated signal transduction may play an important role in CD8+ T lymphocyte accumulation in lung tissues of rats with COPD. The phospholipase C inhibitor U73122 attenuated not only the accumulation of CD8+ T lymphocytes but also inhibited the production of MMP9 and MMP12 in rats suffering from COPD.