模拟产伤法构建小鼠肛提肌损伤模型及效果评价

Establish and evaluate the levator ani muscle damage of mouse by simulated birth injury

目的探索有效的小鼠肛提肌损伤模型构建方法。方法于2018年8~11月,选取40只SPF级雌性未孕未生育C57BL/6小鼠为研究对象。随机将小鼠分为假手术对照组、单纯阴道扩张组、阴道扩张+远端牵引10 g组、阴道扩张+远端牵引30 g组、阴道扩张+远端牵引60 g组,每组8只,共5组。在损伤24 h后固定小鼠肛提肌,通过HE染色及透射电镜扫描技术分析比较各处理条件下的损伤情况。结果 HE染色结果显示:与对照组相比,单纯阴道扩张小鼠肛提肌组织未见明显损伤;阴道扩张+10 g砝码牵引1 h组肛提肌肌间隙略增大,组织间少量炎性细胞浸润;阴道扩张+30 g牵引1 h组,肛提肌肌束紊乱,肌间隙明显增大,肌纤维小灶性坏死;阴道扩张+60 g牵引1 h后能够造成明显的肛提肌损伤,肌纤维大量坏死,炎性细胞浸润,增生肌纤维中见核内移。透射电镜结果显示:阴道扩张+30 g牵引1 h组小鼠肛提肌灶性坏死、溶解,坏死部位线粒体扩张、空泡化,肌小节结构不完整,肌纤维宽窄不一、排列不规则。结论阴道扩张+机械牵引对小鼠肛提肌造成的损伤程度明显大于单纯阴道扩张,且呈现随牵引力递增趋势,阴道扩张+30 g机械牵引1 h已能造成较明显的损伤。

Objective To explore the feasible method to construct a mouse model of levator ani muscle(LAM) injury.Methods From August to November 2018, 40 SPF non-pregnant female C57 BL/6 mice were selected. Mice were randomly divided into 5 groups, control group(CON), vaginal dilatation group(VD), vaginal dilatation+distal traction group of 10 g(VD+DT 10 g), vaginal dilatation+distal traction group of 30 g(VD+DT 30 g) and vaginal dilatation + distal traction group of 60 g(VD+DT 60 g), 8 mice in each group.LAM of each was fixed 24 hours after the injury, and analyzed by HE staining and transmission electron microscopy(TEM).Results The results of HE staining showed that: compared with the control group, the LAM of the mice in VD showed no obvious injury. LAM in VD+DT 10 g group resulted in slightly enlarged intramuscular space and a small amount of inflammatory cell infiltration. In the VD+DT 30 g group, the LAM was disorganized, the intramuscular space was significantly enlarged, and some muscle fiber was necrotic. LAM in VD+DT 60 g had obvious damage with massive necrosis of muscle fibers, inflammatory cell infiltration, and incomplete perimysium. The results of TEM showed that in the group of VD+DT 30 g, ALM showed focal necrosis and dissolution, mitochondrial dilatation and vacuolation, incomplete perimysium, uneven muscle fiber width and irregular arrangement.Conclusion The injury of LAM caused by VD+DT was significant than VD alone, and showed an increasing damage trend with increasing traction,vaginal dilation +30 g mechanical traction for 1 h can cause obvious damage.