保留变性真皮厚度对深Ⅱ度烧伤猪植皮成活率的影响

Influence of the depth of retained denatured dermis on the survival rate of grafted skin in burn swine with deep partial-thickness burn

目的探讨保留变性真皮厚度对深Ⅱ度烧伤猪植皮成活率的影响。方法将7只中国家猪脊柱两侧各造成4个深Ⅱ度烧伤创面，将其中6只猪的创面按照随机数字表法分为0．25、0．50、0．75、1．00mm组，每组12个创面，分别接受相应厚度削痂自体皮移植术。削痂前在每个创面中心部位采集活检组织样本测量烧伤组织厚度及行组织学观察，削痂后在每个创面中心附近采集活检组织样本测量保留变性真皮厚度及行组织学观察。余1只猪的8个创面设为对照组，不行削痂植皮术，同前取标本后行暴露疗法。伤后即刻到伤后3个月，观察5组创面大体情况。伤后8d，计算0．25、0．50、0．75、1．00mm组创面植皮成活率（以中位数表示）。记录5组创面愈合时间。伤后3个月，再次获取5组创面标本，透射电镜下观察超微结构变化。对数据行成组设计多样本比较的秩和检验、单因素方差分析、LSD检验。结果本实验中烧伤组织厚度为（1．120±0．211）mm。0．25、0．50、0．75、1．00mm组创面保留变性真皮厚度分别为（0．830±0．031）、（0．701±0．010）、（0．382±0．031）、（0．141±0．040）mm。伤后8d，0．25、0．50mm组创面所植皮片全部坏死；0．75mm组创面所植皮片大部分坏死；1．00mm组创面所植皮片大部分成活，少部分溶脱；对照组创面逐渐溶痂。伤后15d，0．25、0．50、0．75mm组创面未成活皮片逐渐脱落，表层有渗出物结痂，1．00mm组创面完全愈合，对照组创面渗出结痂面积最大。伤后3个月，0．25、0．50、0．75mm组和对照组愈合创面因瘢痕收缩而缩小，1．00mm组创面未见明显瘢痕。0．25、0．50、0．75、1．00mm组创面植皮成活率差异有统计学意义（Y。=19．421，P〈0．001）。1．00mm组创面植皮成活率最高为70％（60％，80％），0．75mm组创面植皮成活率为20％（0，30％），0．25、0．50mm组创面植皮成活率均为0（0，0）。5组创面愈合时间差异有统计学意义（F=41．450，P〈0．001）。0．25、0．50mm组创面愈合时间分别为（18．2±1．5）、（18．74-2．3）d，与对照组相近[（18．4±1．7）d，P值均大于0．05]；0．75mm组创面愈合时间为（14．9±2．6）d，与0．25、0．50mm组及对照组比较差异有统计学意义（P值均小于0．01）；1．00mm组创面愈合时间为（9．5±1．2）d，较另4组创面愈合时间均明显缩短（P值均小于0．01）。削痂前，5组创面真皮深层可见炎性细胞浸润带；削痂后植皮前，0．25、0．50、0．75、1．00mm组创面断层表面至炎性细胞浸润带厚度各不相同，对照组创面可见较多炎性细胞。伤后3个月透射电镜下观察示，1．00mm组创面真皮内可见较多Fb，其粗面内质网丰富，细胞器结构较完善。结论伤及真皮深层的深Ⅱ度烧伤，保留烧伤变性真皮0．10rnm左右行自体薄皮片移植术，有利于真皮功能重建，减轻瘢痕生长。

Objective To explore the influence of the thickness of retained denatured dermis on the survival rate of grafted skin in swine with deep partial-thickness burn. Methods Four deep partial-thick- ness wounds were reproduced respectively on both sides of spine in 7 Chinese domestic pigs. The wounds of 6 pigs were divided into 0.25,0.50, 0.75, and 1.00 mm groups with 12 wounds in each group according to the random number table. Tangential excision and autoskin grafting were performed. Before the tangential excision, I tissue specimen was harvested from the center of each remaining wound for the estimation of the depth of burn, and histological observation was done. After the tangential excision, 1 tissue specimen was harvested from the area near the center of each wound for the measurement of the depth of retained denatured dermis with histological examination. The 8 wounds of one pig were set as the control group, and the opera- tion was done, and then they were treated with exposure treatment after biopsy specimens were taken with a- bove-mentioned method. The general condition of wounds in 5 groups was observed from immediately after injury to post injury month （PIM） 3. On post injury day （PID） 7, the survival rate of grafted skin was ob- served in 0.25, 0.50, 0.75, and 1.00 mm groups. Wound healing time was recorded. At PIM 3, the spec- imens were harvested from the wounds of 5 groups, and their ultra microstructures were observed by trans- mission electron microscope. Data were processed with rank-sum test, one-way analysis of variance, anti LSD test. Results The depth of the burn tissue was （ 1. 120 ± 0.211 ） mm. The depths of retained dena- tured dermis in0.25, 0.50, 0.75, and 1.00 mm groups were respectively （0.830 ±0.031）, （0.701 ± 0.010）, （0.382±0.031）, and （0.141 ±0.040） mm. At P1D 8, all grafted skin in0.25 and 0.50 mm groups became necrotic; most grafted skin in 0.75 mm group was necrotic; most grafted skin in 1.00 mm group survived with only a few became necrotic and separated from the wounds. The scabs were gradually separated from the wounds of control group. On PID 15, the grafted skill whieh did not survive in 0.25, 0.50, and 0.75 mm groups was gradually separated from the wounds with exudate forming scab on the sur- face in varying degrees, while the wounds in 1.00 mm group were all healed, and the incidence of scabs for- mation was highest in control group. At PIM 3, sear contraction was found in 0.25, 0.50, 0.75 mm groups and control group, while no obvious scar was observed in 1.00 mm group. There were statistically significant differences in the survival rate of grafted skin in 0.25, 0.50, 0.75, and 1.00 mm groups （X 2 = 19. 421 , P 〈0.00i ）. The survival rate was the highest in 1.00 mm group [10% （60% , g0% ） ] , while the surviv- al rate was 20vk （0, 30ek ） in 0.75 mm group, and it was in both 0.25 and 0.50 mm groups with non-sur- vival of all the grafted skin. There were statistically significant differences in the wound healing time among 5 groups （ F =41. 450, P 〈0. 001 ）. The wound healing time in 0.25 and 0.50 mm groups were respectively （ 18.2± 1.5 ） , and （ 18.7 ± 2.3 ） d, not statistically signifieant different from that of control group [ （ 18.4 ± 1.7） d, P values both above 0. 05 ] . The wound healing time in0.75 mm group [（14.9±2.6） d] wassig- nificantly different from those of 0.25, 0.50 mm groups and control group （ P values all below 0.01 ）. The wound healing time in 1.00 mm group [ （9.5 ±1.2） d] was significantly shorter compared with that of the other 4 groups （ P values all below 0.01 ）. Before tangential excision, the zone of infiltration of the imflam- matory cells was observed in the deep dermis of wounds in 5 groups. After tangential excision and before au- toskiu graining, the depth from the fault surface to the zone of infiltration of the inflammatory cells varied in 0.25 , 0.50, 0.75, and l. 00 nlm groups while more inflammatory cells were observed in control group. At PIM 3, many fibroblasts were observed in the dermis of wounds in 1. O0 mm group witb abundant rough en- doplsmic retieulum and basically intact organelles. Conclusions Performing autologous skin grafting on deep partial-thickness burn, in which the depth of retained denatured dermis was 0.10 mm, may help regen- erate dermal function and alleviate scar formation.