分别于兔耳薄、厚皮肤处制备的增生性瘢痕增生程度对比观察

Comparative observation on proliferative degree of hypertrophic scars made from thin and thick skin of rabbit ears

目的对比观察分别于兔耳薄、厚皮肤处制备的增生性瘢痕增生程度。方法将8只兔子分为模型组和空白组各4只,模型组每耳选定4个位点,分别为2处薄皮肤的位点(皮肤厚度<1 mm)和2处厚皮肤的位点(皮肤厚度>1.3 mm),每个位点中心至少间隔2 cm,厚皮肤和薄皮肤各做16个位点,在选定位点钻出环形伤口制备HS模型;空白组不作任何处理,正常喂食。观察术后不同时点兔耳创面变化,另观察不同厚度兔耳HE染色、Masson染色,计算兔耳瘢痕增生指数(HI)、成纤维细胞数目(NA)、胶原纤维面积密度(AA)。结果模型组术后第7~42天,随着时间变化,薄皮肤处和厚皮肤处手术后均形成HS,但厚皮肤处更为明显;空白组厚皮肤处和薄皮肤处正常皮肤在观察期内无明显变化。空白组正常皮肤厚处与薄处HE染色无明显差异;模型组HE染色显示薄处与厚处造模的瘢痕均较对应部位正常皮肤显著升高,其中厚处造模的瘢痕显著高于薄处造模的瘢痕。与空白组薄处皮肤比较,模型组薄处皮肤的表皮和真皮明显增厚,真皮中的微血管和成纤维细胞含量增多,未见瘢痕真皮中的毛囊、汗腺等皮肤附属器,NA明显高于空白组薄处皮肤;与空白组厚处皮肤比较,模型组厚处皮肤的变化基本同模型组薄处皮肤;与模型组薄处皮肤比较,模型组厚处皮肤的表皮和真皮的厚度、NA明显高于模型组薄处皮肤。普通光镜下胶原染色显示为蓝色,空白组薄处和后出皮肤的胶原纤维呈网状分布,排列整齐;模型组薄处和厚处皮肤的胶原纤维呈片状或团块状分布,排列紊乱,可见特征性漩涡状胶原结节。与空白组比较,模型组HI和NA增加(P均<0.05);与同组薄处皮肤比较,模型组HI和NA增加(P均<0.05)。结论相较于兔耳薄处皮肤,在厚处皮肤造模,能获得增生程度更为明显,即外观和病理特征更为典型、维持更稳定的增生性瘢痕。

Objective To compare the proliferative degree of hypertrophic scars made from the thin and thick skin of rabbit ears.Methods Eight rabbits were divided into the model group(n=4)and blank group(n=4).In the model group,4 sites were selected in each ear,which were 2 thin skin sites(skin thickness<1 mm)and 2 thick skin sites(skin thickness>1.3 mm);each site was at least spaced 2 cm,16 sites each were made on the thick skin and thin skin,and the circular wound was drilled out of the selected site to make HS models;the rabbits in the blank group were fed normally without any treatment.The wound changes of rabbit ears were observed at different time points after operation,and HE staining and Masson staining of rabbit ears with different thickness were observed.Scar hyperplasia index(HI),the num⁃ber of fibroblasts(NA),and the area density of collagen fibers(AA)were calculated.Results From the 7th day to the 42nd day after operation in the model group,HS was formed in both thin skin and thick skin,but it was more obvious in thick skin,while there was no significant change in normal skin in thick skin and thin skin in the blank group during the observation period.There was no significant difference in HE staining between the thick and thin parts of the normal skin in the blank group,but in the model group,the scars in the thin and thick parts were significantly higher than those in the corresponding parts of the normal skin,and the scar in the thick part was significantly higher than that in the thin part.Compared with the thin skin of the blank group,the epidermis and dermis of the thin skin of the model group were signifi⁃cantly thickened,the content of microvessels and fibroblasts in the dermis increased,the skin appendages such as hair fol⁃licles and sweat glands in the scar dermis were not seen,and the NA was significantly higher than that of the thin skin of the blank group.Compared with the thick skin of the blank group,the change of the thick skin of the model group was basi⁃cally the same as that of the model group.Compared with the thin skin in the model group,the thicknesses of epidermis and dermis and NA in the thick skin in the model group were significantly higher than those in the model group.Under the ordinary light microscope,the collagen staining showed blue,the collagen fibers in the thin and posterior skin of the blank group were distributed in a network and arranged neatly,while in the model group,the collagen fibers in the thin and thick skin were distributed in flakes or clumps and arranged in disorder,and the characteristic swirl collagen nodules could be seen.Compared with the blank group,HI and NA increased in the model group(all P<0.05),and HI and NA increased in the model group in comparison with those in the thin skin(both P<0.05).Conclusion Compared with the thin skin of rabbit ears,modeling in thick skin can obtain a more obvious degree of hyperplasia,that is,the appearance and patho⁃logical features are more typical and the hypertrophic scars are more stable.