观察封闭负压治疗对猪深Ⅱ度烧伤创面的影响。

采用控温控压电烫仪在3只普通家猪背部对称制造深Ⅱ度热力烧伤模型，每只猪背6个创面(共18个)，左右对称创面视为一对，共9对创面随机分为持续负压组、间歇负压组、常规换药组。造模24 h后两负压组分别给予持续及间歇封闭负压治疗，压力值均为－125 mmHg(1 mmHg＝0.133 kPa)，常规换药组给予常规换药治疗。于治疗后当天、第3、6、9、14天，分别测量创面面积并计算愈合率；取创面组织进行常规苏木精-伊红(HE)染色，光学显微镜下观察病理学变化，采用免疫组织化学染色法计算细胞增殖指数(PI)及血管内皮细胞计数；记录最终创面愈合时间。数据行单因素方差分析及LSD－t检验。

(1)治疗后第3天，持续负压组、间歇负压组创面愈合率分别为(18.51±4.38)%、(14.26±5.98)%，均高于常规换药组(3.86±2.35)%，差异有统计学意义(t ＝56.552、40.139，P﹤0.05、＝0.001)，治疗后第6天，两负压组分别达(24.74±3.25)%、(20.55±3.43)%，仍高于常规换药组(13.41±4.08)%，差异有统计学意义(t＝5.473、3.432，P﹤0.05、＝0.004)，治疗后第9天，其愈合率分别达(49.81±3.88)%、(46.96±3.16)%，均高于常规换药组(34.29±6.69)%，差异有统计学意义(t＝5.563、4.541，均P﹤0.05)。(2)持续负压组、间歇负压组愈合时间分别为(11.67±0.52)d、(11.50±1.05)d，均短于常规换药组(13.00±0.89)d，差异有统计学意义(t＝2.715、3.055，P＝0.016、0.008)，两负压组间比较，差异无统计学意义(t ＝0.340，P＝0.739)。(3)治疗后第3天，常规换药组创面炎症细胞浸润较两负压组重，其高峰持续到第9天，第14天逐渐消退。(4)治疗后第3天，持续负压组和间歇负压组细胞PI明显升高，高于常规换药组，差异有统计学意义(t＝10.413、9.080，均P﹤0.05)，治疗后第6天分别达高峰，仍高于常规换药组，差异有统计学意义(t ＝4.549、5.557，均P﹤0.05)，治疗后第9、14天，3组细胞PI无明显差异。(5)治疗后第3、6天，持续负压组、间歇负压组血管内皮细胞计数均高于常规换药组，差异有统计学意义(均P﹤0.05)。治疗后第9、14天，3组血管内皮细胞计数差异无统计学意义(F＝1.639、1.711，P＝0.218、0.205)。

与常规换药相比，封闭负压引流治疗能加快创面坏死组织清除，促进创面炎症反应消退，加速深Ⅱ度烧伤创面愈合。

To investigate the effect of Vacuum-assisted closure(VAC) technology on deep partial-thickness burn wound of pigs.

A total of 18 deep partial-thickness burn wounds were established by the temperature and pressure controlled perm instrument on 3 ordinary pigs back symmetrically, 6 per pig. The wounds were randomly divided into 3 groups: which were treated by vacuum-assisted closure therapy with continuous model, discontinuous model or treated by conventional dressing therapy corresponding. The wounds were placed without any treatment in 24 hours, after that, the two VAC therapy groups were given corresponding modes of vacuum-assisted closure treatment with the pressure of -125mmHg, while conventional dressing therapy group received iodophor vaseline gauze dressing treatment. The dates of wound area, wound healing rate were collected and analyzed at right away、3、6、9、14 days post treatment. Specimens from wounds were harvested for histopathology observation, including cell proliferation index and the number of vascular endothelial cells. The dates were analyzed by one way ANOVA and multiple group comparison with LSD-t test.

(1)On the third day after treatment, the healing rate of VAC therapy group with continuous model and discontinuous model were (18.51±4.38)%, (14.26±5.98)%, which were higher than the conventional dressing therapy group(3.86±2.35)%(t =56.552、40.139, P﹤0.05, =0.001). On 3 d, the healing rate of both VAC therapy group were(24.74±3.25)%, 20.55±3.43)%, which were still higher than the conventional dressing therapy group(13.41±4.08)%(t=5.473, 3.432, P﹤0.05, =0.004). On 9 d, those were (49.81±3.88)%, (46.96±3.16)%, which were higher than the conventional dressing therapy group(34.29±6.69)%(t=5.563, 4.541, P﹤0.05). (2)The healing time of VAC therapy group of continuous model was (11.67 ± 0.52) d, while that discontinuous model was (11.50 ± 1.05) d, both were statistically difference compared to the conventional dressing therapy group (13.00 ± 0.89) d(t=2.715, 3.055, P=0.016, 0.008). There was no statistically difference between the both VAC therapy groups (t =0.340, P=0.739). (3)On the third day after treatment, the infiltration of inflammatory cells in wounds of the conventional dressing therapy group were higher than that in both VAC therapy groups, which was peaked on 9 d and faded on 14 d. (4) On the third day after treatment, the cells PI of the both VAC therapy groups were increased, which were higher than conventional dressing therapy group (t=10.413, 9.080, P﹤0.05). The cells PI of the both VAC therapy groups were peaked on 6 d, which were still higher than conventional dressing therapy group (t=4.549, 5.557, P﹤0.05). No statistically significant difference was founded between the 3 groups on the ninth and fourteenth day after treatment(F=0.488, 0.630, P=0.621, 0.542). (5) On the third and sixth day after treatment, the numbers of vascular endothelial cells of the both VAC therapy groups were higher than conventional dressing therapy group (P﹤0.05). No statistically significant difference was founded between the 3 groups on the treatment of 9 d and 14 d (F=1.639, 1.711, P=0.218, 0.205).

Compared with conventional dressing change, vacuum-assisted closure therapy can speed up the removal of necrotic tissue, accelerate wound inflammation subsided, promote the healing process of deep partial-thickness burn wounds.