| Objective:Through ultrapulsed fractional CO2 laser establish drug delivery pathway treating melasma guinea pig model, testing model lesional melanocytes and melanin granules changes, explore ultrapulsed fractional CO2 laser combined with tranexamic acid external application on melasma therapeutic significance spot.Method:30 healthy female guinea pigs, in which 20 of the model group,10 normal group. Cut off their back area hair about 4x4cm2. Model group were given daily intramuscular injection of 0.4% progesterone,5ml/kg, while the 320nm wavelength ultraviolet irradiation the exposed back skin, once a day,60 minutes a time, for 30 days, guinea pig animal model chloasma. After modeling is complete, take the normal group and model group skin of guinea pigs, check the skin superoxide dismutase (SOD) and malondialdehyde (MDA) content, and histological observation, confirmed melasma guinea pig model successfully established. After modeling the skin of guinea pigs divided into four regions, namely:Group A:normal group; Group B:ultrapulsed fractional CO2 laser treatment group; Group C:ultrapulsed fractional CO2 laser+ tranexamic acid external application group; Group D:tranexamic acid external application group. Take normal skin of guinea pigs, model guinea pig skin, and 3 days,14 days,30 days after treatment guinea pig skin, HE staining, melanin granules staining (Masson Fontana staining) to observe changes in the number of melanin granules. Analysis of epidermal melanin granules number of changes before and after treatment using image analysis. The data entered into the computer with SPSS 20.0 software for statistical analysis to p<0.05 was considered statistically significant.Results:20 modeling guinea pigs, In the modeling process clearly visible stain formation, accompanied with skin redness, dryness, scaling and other reactions,20-30 days after irradiation showing a uniform and stable dark brown spots. Take after modeling skin of guinea pigs detection:SOD content of the normal set of indicators with the model group, compared with a significant difference (p<0.05). MDA content of the normal set of indicators with the model group, compared with a significant difference (p<0.05). Resulting in a decrease in line with SOD, MDA increased trend, indicating that melasma guinea pig animal model was successfully established.General observation:Group A:pigmentation over time slightly decreased, the first 30 days was still significantly higher than normal skin. Group D:pigmentation slightly decreased after 30 days of treatment was still significantly higher than normal skin. Group B and Group C: immediately after laser treatment, the treatment area of guinea pigs skin splashing dandruff, but no significant bleeding, wound 2-3 days after treatment began to scab, and scab film formed on the skin treatment area, Group B:ultrapulsed fractional CO2 laser treatment group, On the 7th day after treatment the visible point dander off; Group C:ultrapulsed fractional CO2 laser+tranexamic acid external application group, scabbing obviously, black scab gradually thicker, drier.21-26 days after treatment scab sloughed off, the treatment group compared with normal skin color is slightly pale skin and red, no obvious signs of relapse pigmentation.Melanin granules staining:After ultrapulsed fractional CO2 laser treatment, melanin granules decreased significantly. GroupA and D: epidermal melanin granules decreased slightly over time, but still significantly higher than normal guinea pig epidermal melanin granules. Group A and Group D showed no significant difference (p>0.05). Group B and Group C can effectively reduce the melanin particles number(p<0.05); The difference between Group C and group B was statistically significant. (p<0.05)By visual score, the number of melanoma, the percentage of positive target area occupies the epidermal area analysis, Ultrapulsed fractional CO2 laser combined with tranexamic acid external application treatment on guinea pigs melasma is more effective than the other three groups. The difference was statistically significant. (p<0.05)Conclusion:1. UV irradiation combined with progesterone attack female brown guinea pigs showed that the skin gradually formed a uniform and stable black patches, pathological morphology indicated that melanocytes cell body enlarged, the number of melanin granules significantly increased, the percentage of melanin granules area was significantly increased. Guinea pig skin tissue SOD content decreased, MDA content increased, which in line with melasma biochemical indexes changing. The model is easy to duplicated, and suit for melasma animal research.2. Ultrapulsed fractional CO2 laser combined with tranexamic acid external application treatment of melasma guinea pig model of safe, effective, faster discharge of melanin granules and phagocytosis, reduce the synthesis of melanin granules. The establishment of a drug delivery route, increasing the transdermal absorption of tranexamic acid injection, can inhibit melanin keratinocyte cell activation, and promote the skin barrier function repair, reduce melasma relapse. |
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