烟雾暴露联合克雷伯杆菌感染诱导大鼠肺小动脉病变的评估

Evaluation of pulmonary arteriolar lesions in rats induced by cigarette smoke exposure combined with Klebsiella infection

目的分析烟雾暴露联合克雷伯杆菌感染诱导大鼠的肺小动脉形态结构的变化,评估肺小动脉病变的严重程度。方法对烟雾暴露联合克雷伯杆菌感染大鼠的肺组织切片(对照组和模型组)进行分析。维多利亚蓝染色切片用于肺小动脉肌化、血管壁厚度、血管阻塞分值、肌性血管的内膜和中膜厚度以及新生内膜增殖度的检测;HE染色切片用于血管周围炎症细胞浸润及丛状病变等形态的观察和检测;VG染色切片用于内膜胶原纤维和肺小动脉胶原纤维面积百分率的观察和检测。综合以上结果,按照Heath-Edwards标准对肺小动脉病变程度进行评级。结果对于血管直径≤50μm的肺小动脉,与对照组比较,模型组非肌性血管百分率显著减少(P<0.01),肌性血管百分率显著增加(P<0.01),部分肌性血管百分率无显著性差异(P>0.05),非肌性血管壁厚度和肌性血管壁厚度均显著增加(P<0.05,P<0.01),非肌性和肌性肺小动脉血管的阻塞分值均显著增加(P<0.05,P<0.01)。对于50μm<血管直径≤100μm的肺小动脉,与对照组比较,模型组的非肌性血管百分率显著减少(P<0.05),肌性血管百分率和部分肌性血管百分率均无显著性差异(P>0.05),肌性血管壁厚度和血管阻塞分值均显著增加(P<0.05),非肌性血管壁厚度和血管阻塞分值均无显著性差异(P>0.05)。对于血管直径≤50μm或50μm<血管直≤100μm的肺肌性小动脉,与对照组比较,模型组内膜厚度和中膜厚度均显著增加(P<0.05,P<0.01),血管周围炎症浸润分值均显著增加(P<0.05,P<0.01)。对照组(n=9)仅1个切片发现新生内膜,新生内膜增殖度为1.61%。模型组(n=10),5个切片存在新生内膜,新生内膜增殖度从1.04%到17.14%。所有切片均未发现丛状病变。对于血管直径≤100μm的肺小动脉,与对照组比较,模型组内膜胶原纤维表达未观察到变化,血管胶原纤维面积百分率无显著性差异(P>0.05)。按照Heath-Edwards标准,模型大鼠的肺小动脉病变未达到Ⅲ级。结论模型大鼠出现了肺小动脉肌化、内膜和中膜增厚等病理表现,血管周围存在轻度到中度的炎症反应。较低的新生内膜增殖度和未出现胶原纤维表达的变化及未出现丛状病变,提示该模型属于Heath-Edwards标准的II级病变。

Objective To analyze the morphological and structural changes to pulmonary arterioles in rats induced by smoke exposure combined with Klebsiella infection,and to evaluate the severity of the pulmonary arteriolar lesions.Methods Pulmonary arteriolar images from lung sections of control and model rats treated with smoke exposure combined with Klebsiella infection were analyzed by qualitative and quantitative method.Victorian-blue-stained sections were used for the detection of pulmonary arteriolar muscularization,vascular wall thickness,vascular occlusion score,the intima thickness and media thickness of muscular arterioles,and neointima proliferation.Hematoxylin and eosin-stained sections were used for the observation and detection of inflammatory cell infiltration and plexiform lesions around arterioles.Van Gieson-stained sections were used for the observation of collagen fibers in the intima and detection of the percentage of collagen fiber area in the arteriolar wall.Based on the above analyses,the degree of pulmonary arteriolar pathology was rated according to Heath-Edwards criteria.Results For≤50μm diameter arterioles,the percentage of non-muscular vessels was significantly decreased(P<0.01),the percentage of muscular vessels was increased(P<0.01),the percentage of partial muscular vessels was not significantly different(P>0.05),the thicknesses of the non-muscular vessel walls and muscular vessel walls were significantly increased(P<0.05,P<0.01),and the occlusion scores of both non-muscular and muscular pulmonary arterioles were significantly increased in the model group compared with the Control group(P<0.05,P<0.01).For 50μm<diameter≤100μm arterioles,the percentage of non-muscular vessels was significantly decreased(P<0.05),the percentages of muscular vessels and partial muscular vessels were not significantly different(P>0.05),the wall thickness and occlusion score of muscular vessels were significantly increased(P<0.05),and the wall thickness and occlusion score of non-muscular vessels were not significantly different in the model group compared with the Control group(P>0.05).Compared with the Control group,the model group showed significantly increased intimal thickness and media thickness and significantly increased perivascular inflammatory infiltration score in both muscular arterioles of≤50μm diameter and 50μm<diameter≤100μm(P<0.05,P<0.01).In the Control group(n=9),only one section with two neointimal lesions was found,and the degree of neointima proliferation was 1.61%.In the model group(n=10),five sections had neointima lesions,and the degree of neointima proliferation was 1.04%to 17.14%.No plexiform lesions were found in any section.For pulmonary arterioles with a diameter of≤100μm,there was no change in the expression of intimal collagen fibers in the model group compared with the Control group,and there was no significant difference in the percentage of collagen fiber area in the vessel walls(P>0.05).According to Heath-Edwards criteria,the pulmonary arteriole lesions in the model rats did not reach grade Ⅲ.Conclusions The model rats showed pathological manifestations such as pulmonary arteriolar muscularization,thickening of the intima and media,and mild to moderate inflammatory reactions around arterioles.The low amount of neointimal proliferation and collagen fibers in the vascular wall and the absence of plexiform lesions suggest that the model may be up to grade Ⅱ lesions,according to the Heath-Edwards criteria.