褪黑素对支气管哮喘小鼠转化生长因子-β及结缔组织生长因子的影响

Effect of Melatonin on Transforming Growth Factor-β and Connective Tissue Growth Factor in Asthmatic Mice

目的探讨褪黑素(MT)对支气管哮喘(哮喘)小鼠转化生长因子-β(TGF-β)及结缔组织生长因子(CTGF)的影响。方法 SPF级BALB/c小鼠40只随机分为4组,每组10只。哮喘组:造模第1天、第7天,小鼠腹腔注射卵白蛋白(OVA)和氢氧化铝混悬液,第14天,用10g.L-1的OVA溶液对小鼠进行雾化激发,每天1次,每次30min,连续2周和4周。MT组:致敏、诱导哮喘方法同哮喘组,在每次激发前30min,腹腔注射MT10mg·kg-1。地塞米松(DXM)组:致敏、诱导哮喘方法同哮喘组,在每次激发前30min,腹腔注射DXM1.5mg·kg-1。对照组:致敏、雾化方法同哮喘组,以9g.L-1盐水替代OVA和氢氧化铝混悬致敏液及雾化液。各组分别于雾化激发2周和4周收集其肺组织,制作石蜡切片,Masson三色染色法观察其呼吸道周围胶原沉积情况;采用实时荧光定量PCR方法检测TGF-βmRNA表达水平;采用免疫组织化学方法检测CTGF表达水平。结果哮喘组肺组织胶原沉积面积(Wcol/Pbm)较对照组、MT组和DXM组增加,MT组、DXM组亦高于对照组(Pa<0.05),MT组与DXM组间比较差异无统计学意义(P>0.05)。哮喘4周组、MT4周组和DXM4周组Wcol/Pbm分别高于其各自对应的2周组(Pa<0.05)。哮喘组、MT组和DXM组TGF-βmRNA均高于对照组,哮喘组亦高于MT组和DXM组(Pa<0.01),MT组与DXM组间比较无统计学差异(P>0.05),哮喘4周组、MT4周组和DXM4周组TGF-βmRNA分别高于其各自对应的2周组(Pa<0.05)。哮喘组CTGF表达较对照组、MT组和DXM组增加,MT组、DXM组亦高于对照组(Pa<0.05),MT组与DXM组间比较无统计学差异(P>0.05)。哮喘4周组、MT4周组和DXM4周组CTGF表达分别高于其各自对应的2周组(Pa<0.05)。结论 MT能降低哮喘小鼠肺组织TGF-βmRNA和CTGF表达水平,部分抑制呼吸道重构,其调节作用与DXM相当。

Objective To explore the effect of melatonin （MT） on transforming growth factor - β （TGF -β） and connective tissue growth factor（CTGF） in asthmatic mice. Methods Forty female BALB/c mice were randomly divided into 4 groups, 10 mice in each group. In asthmatic group ： mice were sensitized on day 1 and day 7 by intraperitoneal injection of mixture of ovalbumin （OVA） and aluminum hydroxide. From day 14, the mice were induced allengic with aerosolized OVA for 30 rain per day for 2 -4 weeks. In MT group. OVA -sensitized mice were injected intraperitoneally with 10 mg·kg^-1 MT 30 min before each OVA challenge. Dexamethasonc（DXM） group： OVA - sensitized mice were injected intraperitoneally with 1.5 mg·kg^- 1 DXM 30 min before each OVA challenge. In control group：OVA inhalation and MT intraperltoneal injection were replaced with saline. After the models were established, the mice were lavaged. Masson staining was used to stain collagen fibers. The changes of TGF -β mRNA were detected through real - time fluorescent quantitative PCR. The protein expression of CTGF was assessed with immunohistochemistry. Results The collagen area（Wcol/Pbm） were enlarged significantly in asthmatic group compared with those in control group, MT treated group and DXM treated group, while Wcol/Pbm in MT treated group and DXM treated group were higher than those in control group（P 〈 0.05 ）. There was no significant difference in Wcol/Pbm between MT treated group and DXM treated group（ P 〉 0.05 ）. Wcol/Pbm was higher in asthmatic group, MT treated group and DXM treated group after 4 weeks than those after 2 weeks ,respectively（ P, 〈 0.05 ）. The mRNA Ievels of TGF - β in asthmatic group, MT treated group and DXM treated group were significantly higher than those in control group, while in asthmatic group it were higher than in MT treated group and DXM treated group, respectively （ P〈 0.01 ）. There were no significant difference between MT treated group and DXM treated group （ P 〉 0.05 ）. The mRNA levels of TGF - β in asthmatic group, MT treated group and DXM treated group after 4 weeks were higher than those after 2 weeks （ P, 〈 0.05 ）. The expressions of CTGF in asthmatic group were significantly higher than those in control group, MT treated group and DXM treated group, while those in MT treated group and DXM treated group were higher than that in control group（ P 〈 0.05 ）. There were no significant difference between MT treated group and DXM treated group（ P 〉 0.05 ）. The mucus area in asthmatic group, MT treated group and DXM treated group after 4 weeks were larger than those after 2 weeks （ P 〈 0.05 ）. Conclusions MT can inhibit the mRNA levels of TGF -β and the expression of CTGF, and partly inhibit airway remodeling, which plays comparatively the same role with DXM.