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目的 探讨地塞米松 (dexamethasone,DXM )能否通过诱导肺内炎性细胞凋亡而减轻博莱霉素所致大鼠肺间质性纤维化。方法 75只SD大鼠随机分为对照组 (C组 )、博莱霉素组 (BLM组 )和地塞米松组 (DXM组 )。于实验的第 1、3、7、14和 2 8天处死动物 ,获取肺泡灌洗液 (BALF) ,行细胞计数、分类、流式细胞仪测定DNA亚二倍体含量 ;观察肺泡炎和肺纤维化程度及凋亡细胞形态 ;DNA片段原位缺口末端标记 (TUNEL)法进行肺组织凋亡细胞半定量。结果 ( 1)BALF细胞计数 :不同时间DXM组均低于BLM组 ,P均 <0 .0 5 ;( 2 )BALF细胞分类 :DXM组中性粒细胞比例除第 1天组外 ,其余各相应时间组均比BLM组明显降低 ,P <0 .0 1;( 3)BALF细胞中凋亡细胞所占比例 :DXM第 14、2 8天组均明显高于相应时间的BLM组 ,P <0 .0 5 ;( 4 )DXM组肺泡炎高峰较BLM组后移 ;纤维化程度也明显低于BLM组 ;( 5 )形态学观察 :DXM各时间组与BLM组比较 :凋亡细胞明显增多 ;BLM 2 8d组肺泡间质胶原明显多于DXM组 ,纤维母细胞增多 ;( 6 )肺组织炎性细胞凋亡指数 :DXM组除第 14天组外 ,其余各时间组凋亡指数均明显大于BLM组 ,P <0 .0 5～ 0 .0 1;( 7)凋亡抑制基因Bcl 2的表达在DXM组明显低于BLM组。结论 DXM通过诱导肺内炎症细胞凋亡增加 ,减轻BLM所致?
Objective To investigate whether dexamethasone (DXM) can attenuate bleomycin - induced pulmonary interstitial fibrosis in rats by inducing inflammatory cell apoptosis in the lung. Methods Seventy - five SD rats were randomly divided into control group (C group), bleomycin group (BLM group) and dexamethasone group (DXM group). The animals were sacrificed on the 1st, 3rd, 7th, 14th and 28th days of the experiment, BALF was obtained, the cell count, classification and DNA sub-diploid content were determined by flow cytometry; Fibrosis and morphological changes of apoptotic cells; semi-quantitative analysis of apoptotic cells in lung tissue by DNA nick end labeling (TUNEL) method. Results (1) BALF cell count: DXM group was lower than that of BLM group at different time points (P <0.05). (2) BALF cell classification: The proportion of neutrophils in DXM group was (P <0.01). (3) The percentage of apoptotic cells in BALF was significantly higher in BLM group than that in BLM group on the 14th and 28th days . (4) The peak of alveolitis in DXM group was more backward than that in BLM group, and the fibrosis degree was also significantly lower than that of BLM group. (5) Morphological observation: Compared with BLM group, the number of apoptotic cells in DXM group increased obviously; Compared with DXM group, the number of fibroblasts in BLM 2 8d group was more than that in DXM group. (6) The index of inflammatory cell apoptosis in lung tissue in DXM group was significantly higher than those in the other groups BLM group, P <0.05 ~ 0. 01; (7) The expression of apoptosis-inhibiting gene Bcl 2 in DXM group was significantly lower than that in BLM group. Conclusion DXM can induce the apoptosis of inflammatory cells in the lung and reduce the BLM.