| Objective:To observe the effect of honokiol on thoracic aorta remodeling,phenotype transformation and proliferation of vascular smooth muscle cells（VSMCs）induced by angiotensinⅡ（AngⅡ）,and to explore the regulatory mechanism of honokiol in improving vascular remodeling,phenotype transformation,proliferation and viability of VSMCs.Methods:Animal experiments:The rat model with vascular remodeling was established through subcutaneously embedding capsules with AngⅡpump for four weeks.The 32 male SD rats were randomly divided into 4 groups:Control group（n=8）,AngⅡgroup（520 ng/kg/min,n=8）,AngⅡ+HKL2.5 group（honokiol 2.5 mg/kg/d,n=8）,AngⅡ+HKL5 group（honokiol 5 mg/kg/d,n=8）.The Control group was injected with the same amount of normal saline subcutaneously.HE staining was applied to observe the morphological structure of thoracic aorta.Immunohistochemistry was used to observe levels of OPN and PCNA in thoracic aorta.Western blotting was used to determine levels of OPN,PCNA,Akt and p-Akt.Cell experiments:The primary vascular smooth muscle cells of thoracic aorta were cultured by tissue adherent method.Cell grouping:I:blank control group（Ctr）,AngⅡ(10-6M)group,AngⅡ(10-6M)+HKL(10-7M)group;Ⅱ:blank control group（Ctr）,AngⅡ(10-6M)group,AngⅡ(10-6M)+MK2206(10-6M)group.Cell counting kit-8（CCK-8）assay was conducted to detect cell viability.The protein levels of OPN,PCNA,Akt and p-Akt were measured by WB.Results:Animal experiments:（1）HE:Compared with the Control group,the area of aortic media and the thickness of aortic wall in AngⅡgroup were significantly increased（P<0.01）,and compared with AngⅡgroup,the area of aortic media and the thickness of aortic wall in AngⅡ+HKL2.5 group and AngⅡ+HKL5 group were significantly decreased（P<0.05）.（2）Immunohistochemistry:Compared with the Control group,the expression levels of OPN and PCNA of in thoracic aorta of AngⅡgroup were significantly increased（P<0.05）.HKL could inhibit the expressions of OPN and PCNA induced by AngⅡ.Compared with AngⅡgroup,the expression levels of OPN and PCNA in AngⅡ+HKL2.5 group and AngⅡ+HKL5 group were significantly decreased（P<0.05）.（3）WB:Compared with the Control group,the expression levels of OPN,PCNA and p-Akt in thoracic aorta of AngⅡgroup were significantly increased（P<0.05）,and compared with AngⅡgroup,the expression levels of OPN,PCNA and p-Akt in AngⅡ+HKL2.5 group and AngⅡ+HKL5 group were significantly decreased（P<0.05）.Cell experiments:（1）CCK8:AngⅡ(10-6M)could promote the proliferation of VSMCs.Compared with Ctr group（blank control group）,the proliferation activity of VSMCs in AngⅡ(10-6M)group was significantly increased（P<0.01）.HKL(10-7m)could significantly inhibit the proliferation activity of VSMCs induced by AngⅡ(10-6M).Compared with AngⅡ(10-6M)group,the proliferation activity of VSMCs in AngⅡ(10-6M)+HKL(10-7M)group was significantly decreased（P<0.01）.（2）WB:AngⅡ(10-6M)could promote the expression of p-Akt,OPN and PCNA in VSMCs.Compared with Ctr group（blank control group）,the expression of p-Akt,OPN and PCNA in AngⅡ(10-6M)group was significantly increased（P<0.01）.HKL(10-7M)and MK2206(10-6M),the inhibitor of Akt,could significantly inhibit the expression of p-Akt,OPN and PCNA in VSMCs.Compared with AngⅡ(10-6M)group,the expression of p-Akt,OPN and PCNA in AngⅡ(10-6M)+HKL(10-7M)and AngⅡ+MK2206(10-6M)groups were significantly decreased（P<0.01）.Conclusion:（1）Honokiol could improve the thoracic aorta remodeling,phenotype transformation and proliferation in AngⅡ-induced rats;（2）Akt inhibitor could inhibit the AngⅡ-induced phenotype transformation and proliferation of VSMCs.（3）Honokiol may improve AngⅡ-induced vascular remodeling,through p-Akt pathway regulating phenotype transformation and proliferation of VSMCs. |
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