| Objective: Steroid-dependent dermatitis is caused by improper use of hormones for a long time,and it has not been uniformly named internationally.The clinical manifestations of the disease include skin erythema,pimples,local atrophy,and sensitivity to external stimuli.Intense pulsed light(IPL),recombinant bovine basic fibroblast growth factor(rhbFGF)has been widely used in clinical treatment of the disease.In this experiment,an animal model of rabbit steroid-dependent dermatitis was established,and IPL irradiation,rhbFGF gel external application and the combination treatment were used to observe the changes of collagen fibers and MMP1 before and after treatment.To provide theoretical basis for the treatment of steroid-dependent dermatitis with IPL and rhbFGF gel.Methods:1.Establish animal models: 12 white rabbits,each shaved on the back to fully expose the skin.Took normal skin and embed in paraffin for later use.The exposed skin was coated with 0.02% clobetasol propionate cream(En Skin Cream)for 80 days.Skin tissues were taken on the 20 th,35th,50 th,65th,and 80 th days after modeling,and epidermal pathology was observed by HE staining,and collagen fiber morphology was observed by Sirius scar staining.2.Experimental grouping and processing: After the model was completed,the back of each rabbit was divided into four quadrants and randomly divided into four groups: A,B,C,and D: Group A was the control group(no treatment),and group B was coated with rhbFGF gel.Group C was irradiated once with IPL,and group D was used in combination.After the IPL irradiation was completed once,the skin tissues of each group were taken at 6 hours,24 hours,72 hours,7 days,14 days,and 21 days to observe the expression of collagen fibers and MMP1.3.Expression of collagen fibers and mmp1: The expression of collagen fibers was observed by Sirius scar staining,and the expression of MMP1 was determined by Western-blot.Use image J to analyze the data.Differences between the normal group and the model group were compared using the t test.Differences between the groups after treatment were analyzed by analysis of variance.P <0.05 was considered statistically significant.Results:1.Animal model establishment: After modeling,the skin gradually appears with flushing,pimples,dry desquamation,thin skin,and visible subcutaneous capillaries.2.Pathological characteristics of the model group: non-specific thickening of the epidermis,peaked on the 50 th day,and then the thickness of the epidermis decreased.The collagen fiber content in the dermis decreased with the prolonged application of steroid,and the shape gradually became slim,distorted and disordered.3.Collagen fiber and MMP1 expression levels in each group: There was a difference in the decrease in collagen fiber volume and the increase in MMP1 expression between the model group and the normal group(P <0.05).Comparing each group with the control group after treatment,there was no significant difference in the expression of collagen fibers and MMP1 in the rhbFGF gel group(P> 0.05).There was a difference in the increase of collagen fiber content and the decrease in MMP1 expression in the IPL irradiation group and the combined treatment group(P <0.05).Conclusion: 1.A rabbit model of steroid-dependent dermatitis was successfully established.2.The expression of collagen fibers and MMP1 in the rhbFGF gel treatment group was not significantly different from that of the control group;the amount of collagen fibers increased and the expression of MMP1 decreased in the IPL group compared with the control group;the expression of collagen fibers increased and the expression of MMP1 decreased most in the IPL combined with rhbFGF gel group.This shows that both IPL and IPL combined with rhbFGF gel treatment can regulate the secretion of MMP1 and promote the regeneration of collagen fibers.However,rhb FGF gel combined with IPL treatment is the most significant way and can effectively promote the repair of skin barrier. |
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