Analysis of the healing of MRSA-infected cutaneous wounds prepared in hereditary diabetic mice

临床上众所周知，细菌感染会延缓慢性皮肤溃疡的愈合。在这项研究中，我们成功地证明了遗传性糖尿病小鼠作为观察感染性伤口愈合过程的模型的实用性。采用耐甲氧西林金黄色葡萄球菌（MRSA）对雌性G57BLKsJ db/db遗传性糖尿病小鼠背部皮肤创面进行全层处理，制备感染性慢性皮肤创面。局部应用耐甲氧西林金黄色葡萄球菌，然后用卡雷普薄膜覆盖伤口。应用后13 d，通过测量创面再上皮化率（%）、肉芽组织面积（mm^2）、毛细血管数量和细菌计数对创面进行组织学评价。结果表明，与正常小鼠相比，糖尿病小鼠的感染性溃疡发生率高，愈合受损。结果表明：(1)有盖创面比开放创面持续时间更长，表现更为严重；(2)感染性创面的实验尺寸为直径为3mm的创面，较大的创面在1个月的潜伏期后仍未愈合；(3)确定1 *10^6为最佳接种量；(4) MRSA感染平均需要4天；(5) mrsa感染的伤口在13天后仍未愈合；(6)甲氧西林敏感（MS）SA N315P和MRSA N315PZR菌株对糖尿病小鼠感染性创面的形成具有相似的致病性。3 mm伤口感染1 * 10^5 QS MRSA 4 d后，每隔一天用纯化蔗糖聚维酮碘处理一次，伤口愈合时间较MRSA感染和未处理的小鼠提前，细菌计数较低。由此可见，在糖尿病小鼠皮肤上制备感染性慢性溃疡是监测感染性伤口愈合过程和评价药物疗效的良好模型。少

It is clinically well known that bacterial infection delays the healing of chronic skin ulcers. In this study, we succeeded in demonstrating the utility of hereditary diabetic mice as a model for observing the healing process in infectious wounds. infectious chronic cutaneous wounds were prepared by applying MRSA (methicillin-resistant Staphylococcus aureus) to two full-thickness wounds created in the dorsal skin of female G57BLKsJ db/db hereditary diabetic mice. MRSA was applied topically, and the wounds then covered by Cathereep film. Thirteen days after the application, the wounds were histologically evaluated by measuring re-epithelialization (%), area of granulation tissue (mm^2), capillary numbers and bacterial count. Results indicated that the diabetic mice had a high incidence of infectious ulcers and impaired healing compared with normal mice.The following new findings were additionally made : (1) the covered wounds persisted longer and showed more severe manifestations than t … More he open wounds ; (2) a three-mm diameter wound was determined to be the appropriate experimental size for infectious wounds as larger wounds did not close after a one-month incubation period ; (3) 1 *10^6 was determined to be the optimum inoculum size ; (4) an average of four days are required to establish a MRSA infection ; (5) the MRSA-infected wounds remained unhealed after 13 days incubation ; (6) the methicillin-sensitive (MS)SA N315P and MRSA N315PZR strains had a similar pathogenicity with respect to the formation of infectious wounds in diabetic mice. When the mice with 3-mm size wounds, infected with 1 * 10^5 QS MRSA for 4 days, were treated with purified sucrose-povidone iodine every other day, their wounds closed earlier and had a lower bacterial count compared with wounds of the MRSA-infected and non-treated mice. Thus these results indicate that an infectious chronic ulcer prepared in the skin of diabetic mice is a good model for monitoring the healing process of infectious wounds and for evaluating the efficacy of agents. Less