| Objective:To study the mechanism of sodium ferulate and Total Glucosides of Paeony, the main components of the powder of Chinese Angelica and Peony which is the classic recipe to treat melasma in Chinese medicine, in inhibiting the UVB-induced pigmentation on the skin of guinea pig, so as to provide a scientific basis and clinical guidance for the application of sodium ferulate and TGP in the treatment of hyperpigmentation skin disease.Methods:By modeling, We selected normal pure white guinea pig as the experimental model to take the ultraviolet (UVB) irradiation. Before the start of the experiment, we did the hair removal treatment on the back of the guinea pig in an experimental area approximately5cm×5cm, then randomly selected one to do the minimal erythema dose testing, and got the result. Without modeling, Group A, with10guinea pigs, was the control group. We treated the remaining guinea pigs with the UVB irradiation twice of the minimal erythema dose daily in4weeks. The40modeling guinea pigs were randomly divided into four groups,including the Saline Group B, Sodium ferulate Group C, TGP Group D, Vitamin C Group E. Saline Group received intraperitoneal injection of100mg/kg of normal saline daily, the other three groups received intraperitoneal injection of100mg/kg of the related drug daily for4consecutive weeks. We took pictures of the experimental skin area on the back of the experimental animals each week to record the skin pigmentation, and alleviating situation of the pigmentation. At the end of all experiments, animals were sacrificed. We respectively detected the quantity of SOD, MDA in the skin tissue of the guinea pigs from control group, saline group and drug groups, observed the basic pathological changes of the skin by HE staining, determined the number of melanin granule cells with Fontana-Masson staining and observed the situation of the melanosome through transmission electron microscopy, so as to study the effect of sodium ferulate and TGP in reducing pigmentation.Results:We used50guinea pigs to complete the experiment. There were skin pigmentation on the back of the experimental skin area of40guinea pigs after UVB irradiation. The pigmentation on the successfully modeled guinea pigs were reduced after drug treatment, there were no significant changes in the control group and saline group. We compared the treatment groups with control group and saline group respectively after2weeks and4weeks, pigment integral difference was statistically significant (Wilcoxon rank sum test, P<0.01), the pigment points of the Sodium ferulate Group, TGP Group, Vitamin C Group were significantly higher than the Control Group and Saline Group. SOD and MDA test results showed that:the quantity of SOD in the skin of the guinea pigs in Saline Group was significantly less than the control group, while MDA was significantly greater than the Control Group, the difference was significant (P<0.01); the quantity of SOD in the skin of the guinea pigs in the Sodium ferulate Group, TGP Group, Vitamin C Group were greater than the Saline Group, while MDA was less were less than the Saline Group, the difference was significant (P<0.01, P<0.05). The pairwise comparison results indicated that:the quantity of SOD in the skin of the guinea pigs in the Sodium ferulate Group is greater than TGP Group, while MDA is less than TGP Group, the difference was significant (P<0.05); the quantity of SOD in the skin of the guinea pigs in the Sodium ferulate Group is greater than vitamin C group, the difference was significant (P <0.05);while MDA is less than vitamin C group, no significant difference (P>0.05).SOD in vitamin C group is greater than TGP group, while MDA is less than TGP group, no significant difference (P>0.05).Fontana-Masson staining results showed that:the difference between the control group and saline group was statistically significant (P<0.05), the number of melanin granule cells in control group was significantly less than the saline group; Comparing saline group with Sodium ferulate Group, TGP Group and Vitamin C Group, the difference was statistically significant (P <0.05), the number of melanin granule cells of the normal saline group was significantly more than Sodium ferulate Group, TGP Group and Vitamin C Group; the difference between Sodium ferulate Group and TGP Group was statistically significant (P<0.05), the number of melanin granule cells of the Sodium ferulate Group was significantly less than the TGP Group; the difference between Sodium ferulate Group and vitamin C Group was statistically significant (P <0.05), the number of melanin granule cells of the Sodium ferulate Group was significantly less than the vitamin C group; the difference between the TGP Group and the vitamin C group had no statistically significance (P>0.05).Conclusion:Sodium ferulate and TGP have played a role in reducing pigmentation of the hyperpigmentation guinea pig model. The mechanism is related to increasing the local guinea pig skin superoxide dismutase activity, inhibiting the lipid peroxidation reaction, inhibiting melanocytesynthesis of cell proliferation and melanin granules. Sodium ferulate and TGP can be used as a new means of curing melasma in traditional Chinese medicine monomer preparations, however, we may need further validation from the clinical dermatology. |
