胆红素干预对肺气肿大鼠模型层黏连蛋白和表皮生长因子表达的影响

The effects of bilirubin concentration on laminin and epidermal growth factor expression in lung tissue and type Ⅱ pneumocytes in smoking rats model

目的观察胆红素干预对肺气肿大鼠模型肺组织和肺泡Ⅱ型上皮细胞(ATⅡ)层黏连蛋白(Ln)及表皮生长因子(EGF)表达的影响.方法健康Wistar大鼠36只,随机分为3组,每组12只.(1)A组:健康对照组;(2)B组:制作肺气肿模型;(3)C组:制作肺气肿模型,每日烟雾暴露前给予间接胆红素灌胃20 mg/kg一次,灌入液量为1.8～2 ml/次.6个月末时处死大鼠,行ATⅡ的分离、纯化和培养.用放射免疫测定法测ATⅡ培养上清液中Ln的含量.间接免疫荧光法和免疫组化法测肺组织Ln及EGF的表达.结果 ATⅡ培养上清液中Ln含量及肺组织Ln免疫荧光表达B组高于A组(均P<0.05);C组低于B组(均P<0.05),但仍高于A组.肺组织EGF的表达B组高于A组(P<0.05);C组低于B组(P<0.05),但仍高于A组.结论胆红素通过下调Ln及EGF在ATⅡ与肺组织中的表达,对肺气肿形成过程中细胞外基质的重塑有一定的影响.

Objective To explore the effects of bilirubin on expression of laminin(Ln) and epidermal growth factor(EGF) in lung tissue and in typeⅡpneumocytes(ATⅡ) in smoking rats.Methods 36 healthy Wistar rats were randomly divided into three groups: a normal group, a smoking-induced emphysema model group(model group), and a bilirubin group (n=12, for each group). According to XU San-lin method, rats both in the model group and the bilirubin group were exposed to smoke for a total of 6 months. Rats in the bilirubin group were pretreated with indirect bilirubin (20 mg·kg -1·d -1) before exposed to smoke once a day. All animals were sacrificed six months later. ATⅡwere isolated, purified and cultured. Ln in ATⅡ culture medium was determined by radioimmunoassay (RIA). We detected Ln in lung tissue with indirect immunofluorescence technique and EGF with immunochemistry.Results In the model group, Ln content in ATⅡ culture medium and in lung tissue[(5.0±0.3)mg/ml,5.67±0.26] increased significantly compared with those in the normal group[(3.2±0.5)mg/ml,2.01±0.74;P<0.05, respectively]. In the bilirubin group, the two indexes [(3.9±0.7)mg/ml,4.18±0.63] decreased significantly compared with those in the model group (P<0.05,respectively), which was higher than the normal group (P<0.05). Expression of EGF in lung tissue of the model group(0.43 ± 0.09) increased significantly compared with that of the normal group(0.14 ± 0.02;P<0.05). The expression of EGF in the bilirubin group (0.34±0.03) decreased significantly compared with the model group (P<0.05), which was higher than that of the normal group .Conclusions Bilirubin was shown to be able to promote the reconstruction of extracellular matrix by decreasing the expression of Ln and EGF in lung tissue and in ATⅡ in the development of emphysema.