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

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 min 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.Dexamethasone(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 intraperitoneal 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(Pa0.05).There was no significant difference in Wcol/Pbm between MT treated group and DXM treated group(P0.05).Wcol/Pbm was higher in asthmatic group,MT treated group and DXM treated group after 4 weeks than those after 2 weeks,respectively(Pa0.05).The mRNA levels 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(Pa0.01).There were no significant difference between MT treated group and DXM treated group(P0.05).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(Pa0.05).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(Pa0.05).There were no significant difference between MT treated group and DXM treated group(P0.05).The mucus area in asthmatic group,MT treated group and DXM treated group after 4 weeks were larger than those after 2 weeks(Pa0.05).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.