【作者】 胡维；

【导师】 王爱民； 王建民；

【作者基本信息】 第三军医大学 ， 外科学， 2011， 博士

【摘要】 目的:1.采用高速破片对兔、羊、猪的后肢肌肉软组织进行致伤,建立一种局部伤情稳定性高、可重复性好的高速破片伤动物模型,用于评价菠萝蛋白酶对高速破片伤的清创疗效。2.提出一种更为简便的高速破片伤清创方法:切开伤道,在伤道内局部使用菠萝蛋白酶,开放引流并延迟缝合。在猪后肢软组织高速破片伤模型中研究并证实菠萝蛋白酶的清创疗效。3.研究菠萝蛋白酶对高速破片伤伤道微环境的改善作用,阐明其促进创伤愈合的机制。方法:1.采用兔、羊各4只,分别为A、B组。猪8只,随机平均分为C、D组。采用“五三”式滑膛枪发射球形破片(枪口速度约850m/s,质量0.375g)致伤A、B、C组动物后肢软组织,相同方法发射圆柱形破片(枪口速度约950m/s,质量0.87g)致伤D组动物,通过观察局部伤情、伤道组织病理分区、细菌量以及细胞因子水平,并分析各指标变异系数(CV)评价模型伤情的稳定性。2.体外实验中,取正常肌肉组织和伤道内失活肌肉组织,置于不同浓度的菠萝蛋白酶溶液中。通过检测组织失重和酶溶液中的总游离氨基酸释放量,研究酶溶液的选择性组织水解作用。体内实验中,取中国长白猪15只,高速球形破片致伤后随机分为5组:手术清创组(E组)、伤道切开组(I组)、菠萝蛋白酶清创组(B组)、伤道切开+菠萝蛋白酶清创组(IB组)以及对照组(C组)。通过检测伤道组织细菌量、组织病理学改变以及伤道愈合时间,评价各组的清创效果。3.取中国长白猪12只,高速球形破片致伤后随机分为3组:伤道切开组(I组)、伤道切开+菠萝蛋白酶清创组(IB组)以及对照组(C组)。通过检测伤道组织血流量、组织氧分压、肿瘤坏死因子-α(TNF-α)、转化生长因子-β(TGF-β)水平以及伤道愈合时间,研究菠萝蛋白酶对高速破片伤伤道微环境的改善作用。结果:1.所有伤道均为单纯软组织贯通伤。B、C组伤道入、出口面积和伤道容积等局部伤情指标的稳定性优于A、D组。伤道组织病理学观察可见典型高速破片伤的组织病理学分区,其中C组的稳定性优于其他3组。细菌量检测显示伤道组织污染程度较重,各组间无显著差异(p>0.05)。伤道组织内TNF-?和IL-6水平在伤后24h内呈逐渐升高趋势,血浆中TNF-?和IL-6水平变化与之类似,但整体水平低,一定程度上反映了创伤后局部及全身炎症反应程度。2.体外实验中,在相同浓度的酶溶液条件下,伤道内失活组织水解比正常组织更快,差异有统计学意义(p<0.05)。浓度为10 mg/mL的菠萝蛋白酶溶液可迅速水解伤道失活组织,对正常组织几乎没有作用。体内实验中,伤道切开+菠萝蛋白酶清创组的伤道组织细菌量与手术清创组相当,显著低于伤道切开组、菠萝蛋白酶清创组以及对照组(p<0.05)。伤道切开+菠萝蛋白酶清创组的伤道愈合时间也更短。3.在伤道切开+菠萝蛋白酶清创组中,伤道组织血流量和氧分压的恢复显著快于伤道切开组和对照组(p<0.05)。伤后48、72小时,伤道切开+菠萝蛋白酶清创组的组织TNF-α水平显著低于伤道切开组和对照组(p<0.05)。与其他两组比较,伤道切开+菠萝蛋白酶清创组的组织TGF-β含量也更高(p<0.05)。伤道切开+菠萝蛋白酶清创组的伤道愈合时间更短。结论:采用“五三”式滑膛枪发射0.375g,射速约850m/s球形破片射击猪后肢,建立的高速破片伤动物模型,伤情稳定,可重复性好,适用于高速破片伤药物清创的疗效评估。菠萝蛋白酶可有效水解、清除高速破片伤伤道内的坏死组织,极大地简化了清创操作。菠萝蛋白酶清创可有效改善高速破片伤伤道微环境,有利于组织修复,促进伤道的愈合。更多还原

【Abstract】 Objective:1. To establish an animal model for assessment on therapeutic effect of debriding medicine on firearm wound.2. To propose a new therapy using topical bromelain as a supplement to wound incision for the debridement of firearm wounds. We clarified the debriding effect of bromelain on firearm wounds in pigs.3. To investigate the effect of bromelain on the microenvironment of firearm wounds, and to understand how bromelain improves healing.Methods:1. 4 rabbits and 4 goats were group A and group B. 8 pigs were divided into group C and group D randomly. Hind limbs of animals in group A, B and C were wounded with spherical projectiles (velocity 850m/s, weight 0.375g) fired by a 53-type musket. Pigs in group D were wounded with cylindrical projectiles. Appearance of wound tracks, histopathologic zonation, bacterial content and cytokine levels of tissues around the wound tracks were measured. Constancy of model was evaluated using coefficient of variation (CV).2. In vitro, muscle tissues around the wound track and normal muscle were incubated in bromelain solutions of different concentrations. Tissue hydrolization was estimated by measuring tissue weight and the release of total amino acids. In vivo, the hind limbs of 15 pigs were wounded with high-velocity projectiles. Five groups were classified: wound excision (E), wound incision (I), bromelain (B), incision + bromelain (IB) and control (C). Debriding effectiveness was estimated using bacterial content, histopathologic examination, and wound healing time. 3. Twelve Chinese landrace pigs wounded by high-velocity projectiles were divided randomly into three groups: wound incision (group I), incision + bromelain (group IB) and control. Blood perfusion, oxygen partial pressure (pO2), and the content of tumor necrosis factor (TNF)-αand transforming growth factor (TGF)-βin wound-track tissue were measured. Wound healing was also noted.Results:1. All wound tracks were simple penetrating wounds. Size of wound track entrance and exit, volume of wound track in group B and group C were more consistent than in group A and group D. Under light microscope, typical histopathologic zonation of firearm wounds was observed, which revealed that the status of injuries in group C was more invariant than the other three groups. Bacterial count showed that contamination to the wound track was heavy, and there was no statistic difference among groups (p>0.05). TNF-αand IL-6 levels in tissues heightened gradually within 24 hours after wounding. The change of TNF-αand IL-6 levels showed a similar trend in the plasma, but the levels were lower relatively.2. In vitro, hydrolization of wound tissue was significantly more intensive than that of normal tissue (p<0.05). Bromelain solution (10 mg/mL) hydrolyzed wound tissue rapidly with minimal proteolysis of normal tissue. In vivo, the wound-track bacterial content of group IB was similar to that of group E, and was significantly lower than that of groups I, B and C. The wound healing time of group IB was also shorter.3. The recovery of blood perfusion in tissue and pO2 in wound tracks was significantly more rapid in group IB than in group I and control (p<0.05). The tissue level of TNF-αwas significantly lower in group IB than in group I and control 48 h and 72 h post-wounding (p<0.05). The tissue level of TGF-βin group IB was sustained at a significantly higher level than in group I and control (p<0.05). Wound healing time was also shorter in group IB.Conclusions:Simple soft tissue penetrating wounds on hind limbs of pigs wounded with spherical projectiles (velocity 850m/s, weight 0.375g) possesses the histopathologic and bacterial characteristics of firearm wound. State of injuries is consistent. Approach to this model is simple. Bromelain is effective in the debridement of uncomplicated firearm wounds if used as a supplement to simple wound incision. This new therapy shows notable advantages over conventional surgical debridement as it greatly simplifies the procedures. Enzymatic debridement using topical bromelain in incised wound tracks ameliorates the wound microenvironment for tissue repair and improves the healing of firearm wounds.更多还原