蛋白激酶C对慢性低氧大鼠肺动脉胶原表达的调控及灯盏花素的干预作用

目的　探讨蛋白激酶C(PKC)对慢性低氧大鼠肺动脉胶原表达的调控作用及灯盏花素的影响。方法　将二级Sprague Dawley(SD)大鼠分为 :对照组 (A) ,低氧组 (B) ,低氧 +灯盏花素组 (C) ,低氧时间为 4周。采用透射电镜、放射活性测定法、免疫组化、原位杂交等方法综合进行评价。结果(1)B组肺动脉平均压 (mPAP)、右心室重量比 (RV/LV +S)显著高于A组 (P <0 0 1) ,C组mPAP、RV/LV +S显著低于B组 (P <0 0 1) ;(2 )电镜显示B组肺动脉胶原纤维较A组明显为多 ,C组较B组明显为少 ;(3)B组肺组织PKC总活性 (PKCt)、胞膜PKC活性 (PKCm)、胞浆PKC活性 (PKCc)及PKCm占PKCt的百分比显著高于A组 (P <0 0 1) ,C组PKCt、PKCm、PKCc及PKCm占PKCt的百分比显著低于B组 (P <0 0 5 ) ;(4)免疫组化显示B组肺细小动脉 (直径 10 0～ 2 0 0 μm)PKC含量 (平均吸光度A值 )显著高于A组 (P <0 0 1) ,C组较B组显著为低 (P <0 0 1) ;(5 )免疫组化和原位杂交显示B组肺细小动脉 (直径约 10 0～ 2 0 0 μm)Ⅰ型胶原及Ⅰ型前胶原mRNA平均A值较A组明显为高 (P <0 0 1) ,C组较B组为低 (P <0 0 1) ,Ⅲ型胶原及Ⅲ型前胶原mRNA平均A值各组间差异无显著性 (P >0 0 5 ) ;(6 )肺组织PKC活性和肺动脉管壁PKC的表达与肺动脉管壁Ⅰ型胶原mRNA和蛋白

Regulation of the expression of pulmonary arterial collagen by protein kinase C and breviscapine in chronic hypoxic rats

OBJECTIVE: To investigate the effects of protein kinase C and breviscapine on the expression of pulmonary arterial collagen in chronic hypoxic rats. METHODS: Thirty-six rats were randomly divided into three groups: control group (A), hypoxic group(B),hypoxic + breviscapine(bre.)group (C). The ultrastructure of pulmonary arterioles was observed by electron microscope; the PKC activities of lung tissues were measured by radioactivity; the expression of PKC and collagen I and III in arterioles was observed by immunohistochemistry; the expression of procollagen I and III mRNA in arterioles was observed by in situ hybridization. The averages of integral light density( A )of PKC, collagen I and III and procollagen I and III mRNA in pulmonary arterioles were detected by image analysor and their relative contents were calculated. RESULTS: (1) The mean pulmonary arterial pressure (mPAP) and the weight ratio of RV to LV + S in group B were higher than those in group A(P < 0.01); the mPAP and the weight ratio of RV to LV + S in group C were lower than those in group B (P < 0.01). (2)Electron microscopy showed breviscapine could inhibit the deposition of collagenous fibers in pulmonary arterioles induced by hypoxia.(3) The total,cytosolic and particulate fractions of PKC activity and the ratio of particulate fraction to total PKC activity in group B were higher than those in group A(P < 0.01); the total,cytosolic and particulate fractions of PKC activity and the ratio of particulate fraction to total PKC activity in group C were lower than those in group B (P < 0.05). (4) The A values of PKC, collagen I and procollagen I mRNA in pulmonary arterioles were higher in group B than in group A(P < 0.01),and the A values of PKC, collagen I and procollagen I mRNA in pulmonary arterioles were lower in group C than in group B(P < 0.01); the differences in the A values of collagen III and procollagen III mRNA in pulmonary arterioles were not significant among the three groups (P > 0.05).(5)There were good correlations between the PKC activity of the lung tissues and the A values of collagen I and procollagen I mRNA in pulmonary arterioles(P < 0.05),and between the A values of PKC in pulmonary arterioles and those of collagen I and procollagen I mRNA in pulmonary arterioles(P < 0.01). CONCLUSIONS: The PKC signal pathway regulates the expression of pulmonary arterial collagen in chronic hypoxic rats which may play an important role in the pathogenesis of pulmonary hypertension and structural remodeling of pulmonary arterials breviscapine can lower hypoxic pulmonary hypertension by inhibiting the effect of PKC and decreasing the expression of pulmonary arterial collagen.