Abstract: Objective To investigate the protective effect of matrine on skin damage induced by ultraviolet exposure in rats and its effect on CYR61-NF-κB-AP-1 pathway. Methods Totally 50 Wistar rats were divided into normal control group,Ultraviolet B （UVB） exposure group,matrine low-dose,medium-dose,and high-dose groups. Except for the normal control group,the depilated areas on the back of each group were exposed to UVB. During the exposure period,matrine corresponding drug smear interventions were given at low,medium and high doses of matrine. The normal control group and UVB exposure group were given equal volumes of distilled water. The experimental period was 8 weeks. After the experiment,the skin hydroxyproline level,skin wrinkle score,skin damage score,skin matrix metalloproteinase（MMP-3,MMP-9） level,interleukin-β（IL-β）,interleukin-6（IL-6）,tumor necrosis factor-α（TNF-α）,cyclooxygenase 2（COX-2）,active oxygen（ROS） level,skin cysteine-rich angiogenesis-inducing factor 61（CYR61）,nuclear factor-kappa B（NF-κB）,activator protein-1（AP-1） mRNA protein levels,and changes in skin pathological structure and collagen levels in rats were measured. Results The levels of hydroxyproline in the UVB exposure group,matrine low,medium and high dose groups were lower than those in the normal control group（all P<0.01）,skin fold scores,skin damage scores,MMP-3,MMP-9 levels,IL-β,IL-6,TNF-α,COX-2,ROS levels,CYR61,NF-κB,AP-1 mRNA protein levels were higher than those in the normal control group（all P<0.01）. The proline level in the low,medium and high doses group of matrine were higher than those in the UVB exposure group（all P<0.01）,while the skin fold score,skin damage score,MMP-3,MMP-9,IL-1β,IL-6,TNF-α,COX-2,ROS,CYR61,NF-κB,and AP-1 mRNA protein levels were lower than those in the UVB exposure group（all P<0.01）,and as the dose of matrine increased,the proline level gradually increased（P<0.01）,and skin fold score,skin damage score,MMP-3,MMP-9,IL-1β,IL-6,TNF-α,COX-2,ROS,CYR61,NF-κB,and AP-1 mRNA protein levels gradually decreased（all P<0.01）,with obvious dose dependence（P<0.01）. The skin structure of the normal control group rats was normal,the skin thickness of UVB exposure group rats increased significantly,collagen density decreased significantly,capillary density decreased,and inflammatory cell infiltration increased significantly. After intervention with matrine,the skin thickness of UVB exposure group rats decreased significantly,collagen density increased significantly,capillary density increased,and inflammatory cell infiltration decreased,with a clear dose-effect relationship. Conclusion Matrine has an obvious therapeutic effect on skin damage after UVB exposure,which can reduce the degradation of skin collagen,at the same time inhibit skin oxidative stress and inflammationreactions. The mechanism may be related to the inhibition of low expression of CYR61,NF-κB,and AP-1 mRNA proteins in the skin by matrine after UVB exposure,thereby inhibiting the activation of the CYR61/NF-κB/AP-1 pathway.

Key words: Matrine, Ultraviolet exposure, Skin damage, Cysteine-rich angiogenesis-inducing factor 61, Nuclear factor-kappa B, Activator protein-1