负载磺胺嘧啶银纳米片治疗轻度烧伤合并耐甲氧西林金黄色葡萄球菌感染小鼠疗效观察

Therapeutic effect of silver sulfadiazine-loaded nanosheets on mild burn injury mice infected with methicillin-resistant staphylococcus aureus

目的探讨负载磺胺嘧啶银(silver sulfadiazine,AgSD)纳米片对轻度烧伤合并耐甲氧西林金黄色葡萄球菌小鼠的治疗效果。方法利用纳米技术制备负载0.1、1.0、10.0、20.0、50.0、100.0μg/cm^2 AgSD颗粒纳米片,应用原子力显微镜观察其形态特征,确定最佳治疗浓度。雄性C57BL6小鼠18只腹腔麻醉后将背部毛发除去,暴露于70℃热水中4s,制备小鼠烧伤模型,1d后在伤口处接种10u耐甲氧西林金黄色葡萄球菌,制备浅度烧伤并耐甲氧西林金黄色葡萄球菌感染模型,并随机分为观察组、治疗对照组、空白对照组各6只。观察组应用负载20.0μg/cm^2 AgSD纳米片进行治疗,治疗对照组应用未负载AgSD的纳米片进行治疗,空白对照组不进行任何治疗,治疗3d后测量3组伤口面积,统计伤口细菌数,显微镜观察烧伤组织病理改变。结果随AgSD浓度增高,纳米片形成的AgSD颗粒增大,AgSD颗粒和纳米片的黏附力降低;确定纳米片负载AgSD的最佳浓度为20μg/cm^2;治疗3d后,观察组伤口感染面积[(25.1±0.9)cm^2]较治疗对照组[(46.3±2.5)cm^2]、空白对照组[(47.1±1.5)cm^2]明显缩小(P<0.01);观察组伤口感染细菌数[(2.1±0.2)×10~2 cfu]较治疗对照组[(1.4±0.2)×10~6 cfu]、[空白对照组(2.5±0.1)×10~6 cfu]明显减少(P<0.01);观察组伤口感染程度较治疗对照组、空白对照组明显减轻(P<0.01)。结论负载AgSD纳米片治疗轻度烧伤合并耐甲氧西林金黄色葡萄球菌感染具有较好的治疗效果。

Objective To explore the therapeutic effect of silver sulfadiazine （AgSD）-loaded nanosheets on mild burn injury mice infected with methicillin-resistant staphylococcus aureus. Methods Nanotechnology was adopted to prepare 0.1, 1.0, 10.0, 20.0, 50.0 and 100.0 μg/cm2 AgSD-loaded nanosheets. The morphology features of nanosheets were evaluated by atomic force microscopy to decide the optimal therapy content. The mice were anesthetized by the intraperitoneal injection of sodium pentobarbital, and their hair was clipped and depilated. The dorsal skin area was exposed to 70 ℃ hot water for 4 s to make a partial-thickness burn injury. The methicillin-resistant staphylococcus aureus was inoculated into the burn injury skin to establish the infection model one day later. Eighteen mice were randomly divided into observation group, therapy control group and blank control group, with 6 mice in each group. Observation group was treated with 20.0 μg/cm2 AgSD-loaded nanosheets, therapy control group was treated with the nanosheet lacking AgSD, and blank control group received no treatment. The area, the bacterial count and the pathological changes of wound were observed after 3-day treatment in 3 groups. Results The particle size increased and the adhesive strength decreased with the increase of AgSD content among these nanosheets. The optimal AgSD content was 20 vg/cm2. The wound infection area was significantly smaller in observation group （（25.1 ± 0.9） cm2） than that in therapy control group （（46.3±2.5） cm2） and bank control group （（47.1±1.5） cm2） （P〈0.01）. The wound bacterial count was significantly less in observation group （（2.1 ±4-0.2） × 10^2 cfu） than that in therapy control group （（1.4±0.2） × 10^6 cfu） and blank control group （（2.5 ± 0. 1） ×10^6 cfu） （P〈 0.01）. The bacterial infection degree was significantly lower in observation group than that in therapy control group and blank control group （P〈0.01）. Conclusion AgSD-loaded nanosheet is effective for mild burn injury mice infected with methicillin-resistant staphylococcus aureus.