JNK/MAPK通路与H7N9禽流感病毒感染小鼠模型肺损伤的关系研究

Relationship between the JNK/MAPK Pathway and Lung Injury in Mice Infected with the Avian Influenza A (H7N9) Virus

H7N9流感病毒感染呼吸道的能力强,感染后的病死率较高。流感病毒感染的肺组织可发生明显的炎症反应、氧化应激反应及细胞凋亡,进而出现肺损伤。c-Jun-N端激酶(c-Jun-N-terminal kinase,JNK)/丝裂原活化蛋白激酶(Mitogen-activated protein kinase,MAPK)通路是细胞内调节凋亡、炎症的重要通路,该通路在H7N9流感病毒感染后肺损伤中的作用仍有待阐明。为了研究JNK/MAPK通路与H7N9禽流感病毒感染小鼠模型肺损伤的关系,本研究将C57BL/6小鼠随机分为对照组、H7N9组、H7N9+SP组,后两组制备H7N9低致病性病毒感染模型,造模后H7N9+SP组给予JNK抑制剂SP600125腹腔注射、连续3d。比较三组小鼠肺组织的病毒拷贝数、形态学改变、细胞凋亡率、炎症细胞因子含量、信号通路分子及凋亡分子表达量。结果显示:与对照组比较,H7N9组大鼠肺组织中H7N9病毒的拷贝数、细胞凋亡率、肿瘤坏死因子-α(Tumor necrosis factor-alpha,TNF-α)、白细胞介素-1β(Interleukin-1β,IL-1β)、白细胞介素-6(IL-6)的含量、JNK的磷酸化水平、Bax、cleaved-caspase-3的表达量明显增加(P<0.05),Bcl-2的表达量明显减少(P<0.05),p38MAPK、ERK1/2的磷酸化水平无明显变化(P>0.05);与H7N9组比较,H7N9+SP组大鼠肺组织中H7N9病毒的拷贝数无明显变化(P>0.05),细胞凋亡率、TNF-α、IL-1β、IL-6的含量、JNK的磷酸化水平、Bax、cleaved-caspase-3的表达量明显减少(P<0.05),Bcl-2的表达量明显增加(P<0.05)。本研究揭示H7N9禽流感病毒感染小鼠的肺损伤部分由JNK/MAPK通路的激活所介导。

The avian influenza A(H7N9)virus can infect the respiratory tract,and high mortality rates after infection have been documented. Influenza virus-infected lung tissue elicits an obvious inflammatory response,oxidative stress and apoptosis,which results in lung injury. The c-Jun-N terminal kinase(JNK)/mitogen-activated protein kinase(MAPK)pathway is important for regulating apoptosis and inflammation in cells. The role of this pathway in lung injury caused by infection by H7N9 has not been elucidated. To study the relationship between the JNK/MAPK pathway and lung injury in mice infected with H7N9. C57BL/6 mice were divided into control group,H7N9 group,and H7N9+SP group. The model of low virus infection was established in the latter two groups. After modeling,mice in the H7N9+SP group were injected(i.p.)with the JNK inhibitor SP600125 for 3 consecutive days. The virus copy number,morphologic changes,apoptosis rate,pro-inflammatory-cytokine contents,signal-pathway molecules and expression of apoptotic molecules in the lung tissue of the three groups of mice were compared. Results showed that compared with the control group,the copy number of H7N9,apoptosis rate,contents of tumor necrosis factor(TNF)-α,interleukin(IL)-1β,IL-6,phosphorylation level of JNK,expression of Bax and cleaved-caspase-3 increased significantly(P<0.05).Compared with the control group,expression of B-cell lymphoma(Bcl)-2 decreased significantly(P<0.05),phosphorylation of p38 MAPK and ERK1/2 did not change significantly in the lung tissue of rats in the H7N9 group(P>0.05). Compared with theH7N9 group,the copy number of H7N9 did not change significantly(P>0.05),the apoptosis rate,contents of TNF-α,IL-1β,IL-6,phosphorylation of JNK,expression of Bax and cleaved-caspase-3 decreased significantly(P<0.05),whereas expression of Bcl-2 increased significantly,in the lung tissues of mice in the H7N9+SP group(P<0.05). The present study suggested that activation of the JNK/MAPK pathway mediated the lung injury in mice infected with H7N9 virus.