不同剂量博来霉素诱导的肺纤维化大鼠模型比较

Comparison of pulmonary fibrosis rat models induced by different dosed of bleomycin

目的 比较不同剂量博来霉素(bleomycin, BLM)气管内滴注诱导的大鼠肺纤维化(pulmonary disease, PF)模型的成功率及稳定性。方法 150只SD大鼠随机分为空白组、BLM低剂量组(BL-L组,3 mg/kg)和BLM高剂量组(BL-H组,5 mg/kg),造模后观察大鼠一般状态、死亡情况、体重变化,第28、42、56、84天检测大鼠深吸气量(inspiratory capacity, IC)、肺活量(vital capacity, VC)、肺准静态顺应性(chord compliance, Cchord)和肺动态顺应性(dynamic compliance, Cdyn),记录肺系数,HE、MASSON染色观察肺组织病理变化,检测肺组织羟脯氨酸(hydroxyproline, HYP)含量,免疫组化检测肺组织胶原蛋白III(collagen type III, COL III)表达。结果 BL-L组与BL-H组的死亡率分别为20%和28%。BL-L组体重在第0~56天低于空白组(P<0.01),第56天以后体重恢复。第0~56天BL-H组体重显著低于空白组和BL-L组(P<0.01)。与空白组比较,第28天,BL-L组肺功能IC、VC、Cchord、Cdyn显著降低(P<0.01,P<0.05),BL-H组IC和Cdyn显著下降(P<0.05),第42天,BL-L组IC、VC、Cchord显著下降(P<0.01,P<0.05),BL-H组IC、VC、Cchord、Cdyn显著下降(P<0.01,P<0.05),且IC、VC、Cchord与BL-L组相比显著降低(P<0.01),第56天,BL-H组Cchord显著低于空白组和BL-L组(P<0.01)。第28天,BL-L组和BL-H组肺系数显著高于空白组(P<0.01),第42~56天,BL-H组肺系数显著高于BL-L组和空白组(P<0.01)。BL-L组在第28~56天可观察到炎性浸润、纤维化条索和COL III表达,第84天纤维化病变几乎消失,BL-H组在28~84天均可观察到显著纤维化病变,COL III表达程度显著高于空白组(P<0.01)。第28~42天,BL-L组HYP含量显著高于空白组(P<0.05,P<0.01),后逐渐下降,第28~84天,BL-H组HYP含量显著高于空白组(P<0.01)。结论 3 mg/kg与5 mg/kg的BLM均可成功制备PF大鼠模型,BL-L组在第28天形成肺纤维化,持续至第42天;BL-H组在第28天形成更严重的肺纤维化,持续至第56天,第84天仍有半数存在中重度纤维化。

Objective To compare the success rate and stability of rat pulmonary fibrosis(PF)models induced by intratracheal instillation of different doses of bleomycin(BLM).Methods One hundred and fifty Sprague Dawley rats were divided randomly into control,low-dose BLM 3 mg/kg(BL-L),and high-dose BLM 5 mg/kg(BL-H)groups.General status,mortality,and weight changes were observed,and the lung inspiratory capacity(IC),vital capacity(VC),chord compliance(Cchord),and dynamic compliance(Cdyn)were detected on days 28,42,56,and 84.Lung coefficients were recorded and pathological changes in lung tissue were observed by hematoxylin and eosin and Masson staining.The lung hydroxyproline(HYP)content was detected and collagen type III(COL III)was detected by immunohistochemistry.Results The mortality rates in the BL-L and BL-H groups were 20%and 28%,respectively.Body weight was significantly lower in the BL-L group compared with the control group on days 0~56,and weight recovery after day 56.Body weight was significantly lower in the BL-H group compared with the control and BL-L groups from days 0~56(P<0.01).Regarding lung function,IC,VC,Cchord,and Cdyn were significantly lower in the BL-L group compared with the control group on day 28(P<0.01,P<0.05),and IC and Cdyn were significantly lower in the BL-H group(P<0.01).IC,VC,and Cchord were significantly decreased in the BL-L group on day 42(P<0.01,P<0.05),while IC,VC,Cchord,and Cdyn were significantly decreased in the BL-H group(P<0.01,P<0.05),and IC,VC,and Cchord were significantly lower compared with in the BL-L group(P<0.01).Cchord was significantly lower in the BL-H group compared with the control and BL-L groups on day 56(P<0.01).The lung coefficients on day 28 were significantly higher in the BL-L and BL-H groups compared with the control group(P<0.01),and were significantly higher in the BL-H group from days 42~56 compared with the BL-L and control groups(P<0.01).Regarding lung histopathology and immunohistochemistry,inflammatory infiltration,fibrotic streaks,and COL III expression were observed in the BL-L group from days 28~56,and almost complete disappearance of the fibrotic lesions on day 84.In contrast,fibrotic lesions could be observed from days 28~84 in the BL-H group,with significantly elevated COL III expression compared with the control group(P<0.01).The HYP content was significantly higher in the BL-L group compared with the control group from days 28~42(P<0.05,P<0.01),and then gradually decreased,and the HYP content was significantly higher in the BL-H group than in the control group from days 28~84(P<0.01).Conclusions Both 3 and 5 mg/kg BLM can successfully induce PF rat models.Rats treated with 3 mg/kg BLM developed fibrosis on day 28,which lasted until day 42 and then gradually recovered.Rats treated with 5 mg/kg BLM developed fibrosis on day 28,and the degree of fibrosis was more severe with the higher compared with the lower dose,with stable fibrotic lesions up to day 56 and moderate-to-severe fibrosis still present in half of the rats until day 84.