| Background and purpose: Due to the long-term exposure of ultraviolet(UV)in sunlight or artificial light source,many patients’ skin exposed to it will appear dry,wrinkled and pigmented,and eventually lead to skin aging,which is called "skin photoaging".In the study of skin cell level,the occurrence and development of skin photoaging is a very complex process,and apoptosis is one of the main influencing factors.Fas and Fas L belong to the tumor necrosis factor family.The high expression of Fas L receptor on the surface of cell membrane can recognize and combine with the target cell FAS,and then start the apoptosis process inside the cell,so as to cause the programmed death of the target cell.Therefore,this experiment is carried out in the animal body.UV irradiation is used to induce the skin photoaging of mice and the traditional Chinese medicine of Lu Codonopsis pilosula is used to treat it.The antagonistic effect of Lu Codonopsis pilosula on the skin photoaging of mice is observed,the expression of Fas and Fas L in the skin tissue of mice in each group is measured,and the amount of apoptosis of mice in each group is measured,so as to explore the role of Lu Codonopsis pilosula in the process of defense and treatment of skin photoaging And mechanism.Material and method:36 Kunming mice were randomly divided into six groups: normal control group(NC),UV model group(UV),Lu Codonopsis pilosula high dose group(L-H),Lu Codonopsis pilosula middle dose group(L-M),Lu Codonopsis pilosula low dose group(L-L)and ve positive control group(VE).The mice in each group were fed with conventional drinking water to adapt to the environment.After one week,the area of shaved hair on the back of each group was about 3 × 3cm2,and then shaved every two days to ensure the exposure of the skin on the back of the mice.UVA + UVB light source was radiated to mice in all groups except NC group.The frequency of irradiation was 6 times a week for 12 weeks.The model mice were treated with different doses of medicine.The UV model group was given normal saline orally every day,the ve group was given vitamin E orally every day,the L-H group,the L-M group and the L-L group were given high dose,medium dose and low dose of Lu Codonopsis pilosula orally every day for two weeks,except NC group,all of them were exposed to ultraviolet light for 14 weeks.At the fourteenth week,the mice in each group were killed,and the skin tissues of the shaved parts on the back of the mice were observed and preserved in the refrigerator at-70 ℃.He staining was used to observe the changes of skin morphology,immunohistochemistry was used to detect the expression of Fas and Fas L in the skin of each group of mice,TUNEL method was used to detect the content and distribution of apoptotic cells.Results:1.Macroscopic observation of the skin on the back of miceIn NC group,there was no UV irradiation during the whole experiment,the back skin was smooth and moist without static wrinkles,the skin had good elasticity,no pigmentation,erythema,ulceration and other adverse manifestations.UV group received UV irradiation and no drug intervention during the experiment,the skin showed dry peeling,rough desquamation,skin thickening,obvious gullies,uneven and leather like changes,skin red and pigmented.In L-H group,L-M group and L-L group,the back skin condition of mice was better than that of UV group.In L-H group,the back skin was improved most obviously,but there were still obvious skin erythema on the back,which was dry and accompanied with a small amount of pigmentation.In L-M group,there were still a small amount of wrinkles on the skin,and the back erythema and pigmentation were obvious.In L-L group,there were still a large number of ecchymosis and scab on the back skin.2.He staining results of skin tissue on the back of miceIn NC group,there was no obvious abnormal change in the skin histology,the epidermis structure was relatively complete,the dermis was rich in collagen fibers,the morphology was normal and orderly,and the arrangement was regular.In the UV group,the thickness of the epidermis increased significantly and varied,some of the epidermis was incomplete,layered or even fuzzy;the dermis was obviously thinner,and collagen fibers were broken,the arrangement was disordered and irregular,and the distribution of inflammatory cells was occasionally seen.Compared with UV group,the skin structure of L-H group was significantly improved,the epidermis was complete and thickened,the junction with dermis was clear,the collagen fiber bundle of dermis was significantly increased,arranged orderly,and no inflammatory cells were found.The skin tissue of L-M group and L-L group was better than that of UV group,but the epidermis was still thickened.Although collagen fibers were broken in the dermis,they were arranged orderly,suggesting that the collagen fiber bundle had a certain degree of repair,but the effect was not as good as that of L-H group.3.The expression of Fas and Fas L in the skin of mice in each group was detected by immunohistochemistry3.1 expression of Fas in mouse skinThe expression of Fas in NC group was lower than that in UV group(P < 0.05).Compared with the UV model group,the expression of Fas in L-H group,L-M group and L-L group after the intervention of l-dangshen was significantly lower(P < 0.05).The expression of Fas in LH group,L-M group and L-L group was higher than that in NC group(P < 0.05).Compared with L-H group,the expression of Fas in L-M group,L-L group and ve group increased slightly,with statistical significance(P < 0.05);compared with L-M group,the content of Fas in L-L group increased,with statistical significance(P < 0.05);compared with L-L group,the content of Fas in VE group decreased,with statistical significance(P < 0.05).3.2 expression of Fas L in mouse skinCompared with the NC group,the expression of FasL in the UV model group was significantly higher(P < 0.05),and compared with the NC group,the expression of Fas L in the UV model group was significantly higher(P < 0.05).Compared with the UV model group,the expression of Fas L in the skin of L-H group,L-M group and ve group decreased significantly(P < 0.05).Compared with L-H group,the content of Fas L in the skin of L-M group and L-L group was higher,with statistical significance(P < 0.05);compared with L-M group,the content of Fas L in the skin of L-L group was higher,with statistical significance(P < 0.05);compared with L-L group,the content of Fas L in the skin of VE group was slightly lower,with statistical significance(P < 0.05).4.Expression of Fas and FasL in mouse skinThe results of correlation analysis showed that there was a positive correlation between Fas and Fas L expression in mouse skin(correlation coefficient: 0.876,P = 0.000).5.TUNEL method was used to detect the apoptosis of skin cells in each group of miceCompared with NC group,the number of apoptosis in UV model group and ludongshen intervention group increased significantly(P < 0.05).Compared with the UV model group,the number of skin cell apoptosis in ludongshen intervention group and ve group decreased significantly(P < 0.05).Compared with L-H group,the number of apoptotic cells in L-M group,L-L group and ve group increased significantly(P < 0.05).Compared with L-M group,the number of apoptosis in L-L group increased significantly(P < 0.05),but there was no significant difference in VE group(P > 0.05).Compared with L-L group,the number of apoptosis in VE group decreased significantly(P < 0.05).Conclusion:1.Lu Codonopsis pilosula can protect mice skin from UV induced light aging damage,and in different dose experiments,high dose protection is the most obvious.2.UV irradiation can promote the over expression of Fas and Fas L in the back skin of mice,and increase the number of apoptosis in the skin,suggesting that the pathogenesis of photoaging may be related to the activation of Fas / Fas L signal transduction pathway and the promotion of apoptosis.3.The content of Fas、Fas L and apoptosis in the skin tissue of mice in each group treated with Lu Codonopsis pilosula were lower than those in the UV model group,suggesting that Lu Codonopsis pilosula oral liquid may achieve the anti photoaging effect by inhibiting Fas / Fas L signal transduction pathway and reducing apoptosis. |
PDF Full Text Request