Protective Effects And Mechanism Of Extracts Of Maize Plumule On Collagen Of Oxidative Damaged Mouse Skin

Under the oxidative stress caused by H₂O₂ and UVA, we studied the effects of extracts of maize plumule on collagen synthesis in mouse skin and mouse dermal fibroblast, in order to investigate the anti-oxidative effects and its mechanism of EMP on mouse skin.The H₂O₂ and UVA damaged mouse skin were duplicated, while the mouse dermal fibroblasts were cultured in vitro in order to duplicate the oxidative damaged mouse dermal fibroblast caused by H₂O₂ and UVA. We used 4 groups in each oxidative damaged model: control group, damaged group, 0501 EMP group, 0502 EMP group. The content of Hyp in mouse skin was detected using biochemistry method; the tissue structure of mouse skin was observed by hemotoxylin and eosin staining method; the mouse dermal fibroblasts were cultured in vitro; the growth curve of cultured mouse dermal fibroblast was obtained using MTT method, while the effects of EMP on the growth activity of mouse dermal fibroblast treated by H₂O₂ and UVA were detected using the same method; RT-PCR was carried out in order to measure the relative expression of four objective mRNAs including type I procollagen, type III procollagen, MMP-1 and MMP-3.Under the oxidative stress caused by H₂O₂, 0501 EMP showed better protective effects on the tissue structure of mouse skin than 0502 EMP; the content of Hyp in 0501 EMP group and 0502 EMP group were 3.9 times(P<0.01) and 2 times(P<0.01) higher than that of H₂O₂ damaged group respectively; the measurement of cell activity by MTT method showed that the absorbance value of mouse dermal fibroblast in 0501 EMP group and 0502 EMP group were 1.6 times(P<0.01) and 1.5 times(P<0.01) higher than that of H₂O₂ damaged group respectively; the type I procollagen expression of mouse skin in 0501 EMP group and 0502 EMP group were 2.4 times(P<0.01) and 1.4 times(P<0.01) higher than that of H₂O₂ damaged group respectively, the numbers of the type III procollagen were 15.4 times(P<0.01) and 7 times(P<0.01) higher respectively, the numbers of the MMP-1 were 37.1%(P<0.01) and 16.2%(P<0.01) lower respectively, and the numbers of the MMP-3 were 20.8%(P<0.01) and 13.8%(P<0.01) lower respectively; the type I procollagen expression of mouse dermal fibroblast in 0501 EMP group and 0502 EMP group were 3.5 times(P<0.01) and 1.8 times(P<0.01) higher than that of H₂O₂ damaged group respectively, the numbers of the type III procollagen were 4.6 times(P<0.01) and 3 times (P<0.01) higher respectively, the numbers of the MMP-1 were 20.6%(P<0.01) and 16.9%(P<0.01) lower respectively, and the numbers of the MMP-3 were 41.3%(P<0.01) and 15%(P<0.01) lower respectively. Under the oxidative stress caused by UVA, 0501 EMP showed better protective effects on the tissue structure of mouse skin than 0502 EMP; the content of Hyp in 0501 EMP group and 0502 EMP group were 2.3 times(P<0.01) and 1.8 times(P<0.01) higher than that of H₂O₂ damaged group respectively; the measurement of cell activity by MTT method showed that the absorbance value of mouse dermal fibroblast in each group had not been affected by UVA; the type I procollagen expression of mouse skin in 0501 EMP group and 0502 EMP group were 2 times(P<0.01) and 1.75 times(P<0.01) higher than that of UVA damaged group respectively, the values of the type III procollagen were 39.8%(P<0.01) and 28.8%(P<0.01) lower respectively, the values of the MMP-1 were 29.5%(P<0.01) and 9.3%(P<0.01) lower respectively, and the values of the MMP-3 were 43.3%(P<0.01) and 19%(P<0.01) lower respectively; the type I procollagen expression of mouse dermal fibroblast in 0501 EMP group and 0502 EMP group were 3 times(P<0.01) and 2.4 times(P<0.01) higher than that of UVA damaged group respectively, the values of the type III procollagen were 1.2 times(P<0.01) and 1.1 times(P<0.01) higher respectively, the values of the MMP-1 were 53.6%(P<0.01) and 43.2%(P<0.01) lower respectively, and the values of the MMP-3 were 32.3%(P<0.01) and 15.6%(P<0.01) lower respectively.In a word, the activity of mouse dermal fibroblast in vitro could be improved by EMP, which could also protect the membrane-like structure of fibroblast and the regular function of hydroxylase from ROS, so that the content of Hyp in mouse skin was stimulated, moreover, the expression of collagen gene was stimulated while the expression of MMPs was inhibited by EMP, the mouse skin fibroblasts were protected by EMP from oxidative damage so that the general structure of mouse skin tissue were preserved. We presumed that EMP could affect the gene expression by eliminating ROS, protecting the membrane-like structure of cell and the regular function of intracellular protein and DNA from ROS. In the end, 0501 EMP showed stronger anti-oxidative effects than 0502 EMP.