■支气管肺发育不良(BPD)与早产儿生存不良相关。宫内感染可加重早产儿肺泡发育的梗阻程度;致病机制尚不清楚。在这项研究中,我们试图确定是否可以通过下调哺乳动物雷帕霉素靶蛋白(mTOR)激活和诱导受BPD影响的肺组织中的自噬来抑制焦亡.
■我们通过腹腔注射脂多糖(LPS)建立了宫内感染引起BPD的新生大鼠模型。随后,使用免疫组织化学评估mTOR水平和焦亡,免疫荧光,TUNEL染色,和西方印迹。采用Shapiro-Wilk检验来评估实验数据的正常性。非配对t检验用于比较两组之间的均值,多组间的比较采用方差分析.
■BPD肺组织中肺上皮细胞的焦亡增加。在对BPD新生大鼠施用mTOR磷酸化抑制剂(雷帕霉素)后,自噬水平升高,而自噬货物衔接子的表达,LC3和p62没有差别。雷帕霉素治疗后,NLRP3,半胱天冬酶-1,半胱天冬酶-1,IL-1β,IL-1β,IL-18/Pro-IL-18,N-GSDMD/GSDMD,pro-caspase-11和caspase-11在BPD肺组织中呈负调控。用自噬抑制剂MHY1485治疗后观察到相反的结果,显示出BPD中焦凋亡的增加和肺泡数量的显着减少。
■雷帕霉素通过抑制mTOR磷酸化和诱导自噬来减轻LPS诱导的BPD新生大鼠的焦凋亡;因此,它可能代表治疗BPD的潜在治疗方法。
Bronchopulmonary dysplasia (BPD) is associated with poor survival in preterm infants. Intrauterine infection can aggravate the degree of obstruction of alveolar development in premature infants; however, the pathogenic mechanism remains unclear. In this study, we sought to determine whether pyroptosis could be inhibited by downregulating mammalian target of rapamycin (mTOR) activation and inducing autophagy in BPD-affected lung tissue.
We established a neonatal rat model of BPD induced by intrauterine infection via intraperitoneally injecting pregnant rats with lipopolysaccharide (LPS). Subsequently, mTOR levels and pyroptosis were evaluated using immunohistochemistry, immunofluorescence, TUNEL staining, and western blotting. The Shapiro-Wilk test was employed to assess the normality of the experimental data. Unpaired t-tests were used to compare the means between two groups, and comparisons between multiple groups were performed using analysis of variance.
Pyroptosis of lung epithelial cells increased in BPD lung tissues. After administering an mTOR phosphorylation inhibitor (rapamycin) to neonatal rats with BPD, the level of autophagy increased, while the expression of autophagy cargo adaptors, LC3 and p62, did not differ. Following rapamycin treatment, NLRP3, Pro-caspase-1, caspase-1, pro-IL-1β, IL-1β, IL-18/Pro-IL-18, N-GSDMD/GSDMD, Pro-caspase-11, and caspase-11 were negatively regulated in BPD lung tissues. The opposite results were observed after treatment with the autophagy inhibitor MHY1485, showing an increase in pyroptosis and a significant decrease in the number of alveoli in BPD.
Rapamycin reduces pyroptosis in neonatal rats with LPS-induced BPD by inhibiting mTOR phosphorylation and inducing autophagy; hence, it may represent a potential therapeutic for treating BPD.