A Study On Alpha Hydroxy Acid Treatment For Melasma Induced By UVB Mouse Model

Objective:In vivo animal models,we studied the effect of Alpha Hydroxy Acid(AHA)on the treatment of UVB induced chloasma model,and explored the influence of AHA treatment on the biochemical indicators and histopathology of the skin of rats,trying to provide experimental theoretical mechanism for the treatment of Chloasma with AHA.Methods:30 healthy female guinea pigs were randomly divided into normal group and model group.There were 6 in the normal group and 24 in the model group.A guinea pig chloasma model was established by referring to domestic and foreign literature.After the modeling was completed,the serum superoxide dismutase(SOD)and malondialdehyde(MDA)were detected in the normal group and the model group of 6 guinea pigs,and the skin pathological examination was examined to verify the success of the chloasma model in guinea pigs.The remaining guinea pigs in the model group were randomly divided into 3 groups,6 in each group.They were divided into A group,the fruit acid treatment group,the B group,the hydroquinone drug positive control group,and the C group naturally restored to the control group.After 8 weeks of continuous treatment,the serum,liver,skin and skin superoxide dismutase(SOD)activity and the content of malondialdehyde(MDA)were compared after treatment.The pathological histomorphology was observed by HE staining and immunohistochemistry on the skin tissue of the lesion.Result:1)The model group of guinea pigs formed a dark brown spot with uniform stability and clear boundary visible to the naked eye for 30 days.2)After modeling,the serum SOD level of guinea pigs in the model group was significantly lower than that in the normal group,and the serum MDA level was higher than that in the normal group,the difference was statistically significant(p<0.05).The change of the biochemical indexes of the chloasma.3)HE staining of skin lesions in model group showed epidermal epithelial hyperplasia,basal layer.We can see that there are continuous distribution of melanin granules,infiltration of inflammatory cells in the dermis,and microvascular proliferation in the dermis and subcutaneous tissue.Immunohistochemistry revealed large clusters of melanin granules in the basal and spinous layers.It was in accordance with the pathological changes of chloasma.4)After treatment,the skin and skin of group A were slightly reddish,without obvious pigmentation,and slightly lighter than normal skin.In group B,the skin was pale and not pigmented.The skin was occasionally dry and desquamative during the treatment.After treatment,the skin pigmentation of C group was significantly lower than that of normal skin after treatment.5)After treatment,SOD activity in group A and group B increased compared with group C,MDA content decreased compared with C group,A group and B group two groups had significant difference compared with C group(P<0.05);there was no significant difference between A group and C group(SOD>0.05).6)After treatment,HE staining showed that the epithelial cells of the guinea pig's epidermis of group C still proliferate obviously,the nucleus is large and the arrangement is disorderly,the microvascular dilatation is still visible in the dermis,and the inflammatory cells are common,and there is no obvious difference from the model group.In group A and group B,the epithelial cell proliferation of the epidermis of guinea pig was obviously reduced,the arrangement was relatively neatly,the microvessel in the dermis did not expand obviously,and the infiltration of inflammatory cells was rare.Immunohistochemistry showed that there was a large number of melanin granules in the basal layer and spinous layer of guinea pigs in group C,and there was no significant difference between them.In group A and group B,there were linear or scattered melanin granules in the basal lamina of mice.Conclusion:1)UVB combined with progesterone induced chlosma rat model was successfully established,consistent with the pathological and biochemical changes of chloasma.2)AHA treatment is effective in treating chloasma,can reduce the pigmentation of chloasma,reduce the MDA content of chloasma model rats,increase the content of SOD,have antioxidant activity,balance the body antioxidant system,and improve the therapeutic effect of chloasma.3)The effect of AHA treatment on the histopathology of guinea pig skin can reduce the number and density of melanin granules.