Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Jiangnan University, 1000 Hefeng Road, Binhu District, Wuxi City, Jiangsu 214122, China.
Department of Respiratory and Critical Care Medicine, Aoyang Hospital Affiliated to Jiangsu University, 279 Jingang Dadao, Zhangjiagang City, Jiangsu 215631, China.
Acta Histochem. 2023 Dec;125(8):152100. doi: 10.1016/j.acthis.2023.152100. Epub 2023 Oct 12.
Idiopathic pulmonary fibrosis (IPF) is considered as a chronic interstitial lung disease with underlying mechanism of IPF remaining unclear, while there are no definitive treatment options. In recent years, scientists have gradually paid attention to the influence of angiogenesis on IPF. Because IPF is a progressive with microvascular remodeling disorder, scientists have postulated that angiogenesis may also be one of the initiating and contributing factors of the disease. Bupleurum is a common natural Chinese herbal medicine with antibacterial, anti-inflammatory, anti-tumor and other pharmacological effects. As the most important active monomer of Bupleurum, Saikosaponin-d (SSd) is a new discovery with anti-pulmonary fibrosis (PF) activity. This study attempts to investigate the role of SSd in the interference of PF through regulation of angiogenesis in IPF through Angiopoietin (Angpt) /Tie receptor 2 (Tie2) pathway.
Randomly, we allocated C57BL/6 mice into four groups (n = 20 in each group). Afterwards, establishment of IPF model was accomplished via intratracheal administration of bleomycin (BLM, 5 mg/kg), while corresponding drug intervention was given accordingly. On 3rd, 7th, 14th and 28th days after modeling, we performed histopathological examination through staining. Meanwhile, immunohistochemistry (IHC) of PF and the expression of related factors were observed, while Ang/Tie2 pathway was assessed by ELISA with the effect of SSd on angiogenesis related proteins in IPF being explored with IHC and Western Blot technique.
Our results showed that SSd could reduce inflammation and PF levels in lung tissue of experimental mice, while levels of angiogenesis-related factors, namely Tie-2, Ang-1 and ANGPT2 (Ang-2), fibrosis- associated factors like Alpha-smooth muscle actin (α-SMA), collagen-I and hydroxyproline in SSd and dexamethasone (DXM) mice were significantly reduced at each time point compared to BLM (p < 0.01). Additionally, we discovered substantial decreased expressions of Ang-1, Ang-2, Tie-2, α-SMA and collagen-I at protein level in SSd and DXM mice at each time point compared to BLM (p < 0.05). Besides, insignificant differences were observed between SSd and DXM groups (p > 0.05).
This study has demonstrated that SSd could down-regulate the expression of ANG-1, Ang-2 and Tie2 in the Ang/Tie2 pathway, and may reduce lung inflammation and PF in BLM-induced mice via inhibition of angiogenesis.
特发性肺纤维化（IPF）被认为是一种慢性间质性肺疾病，其发病机制尚不清楚，目前也没有明确的治疗方法。近年来，科学家们逐渐关注血管生成对 IPF 的影响。由于 IPF 是一种伴有微血管重构障碍的进行性疾病，科学家们推测血管生成也可能是疾病的启动和促进因素之一。柴胡是一种常见的天然中草药，具有抗菌、抗炎、抗肿瘤等多种药理作用。柴胡皂苷 d（SSd）作为柴胡的最重要活性单体之一，是一种具有抗肺纤维化（PF）活性的新发现。本研究试图通过 Angiopoietin（Angpt）/Tie 受体 2（Tie2）通路探讨 SSd 通过调节血管生成在 IPF 中对 PF 的干扰作用。
将 C57BL/6 小鼠随机分为四组（每组 20 只）。然后，通过气管内给予博莱霉素（BLM，5mg/kg）建立 IPF 模型，并给予相应的药物干预。在建模后第 3、7、14 和 28 天进行组织病理学检查。同时，观察 PF 的免疫组织化学（IHC）和相关因子的表达，通过 ELISA 评估 Ang/Tie2 通路，并用 IHC 和 Western Blot 技术探讨 SSd 对 IPF 中血管生成相关蛋白的影响。
结果显示，SSd 可降低实验小鼠肺组织的炎症和 PF 水平，同时 SSd 组和地塞米松（DXM）组各时间点的血管生成相关因子 Tie-2、Ang-1 和 ANGPT2（Ang-2）、纤维化相关因子α-平滑肌肌动蛋白（α-SMA）、胶原-I 和羟脯氨酸水平均明显低于 BLM 组（p<0.01）。此外，SSd 组和 DXM 组各时间点的 Ang-1、Ang-2、Tie-2、α-SMA 和胶原-I 蛋白水平表达均明显低于 BLM 组（p<0.05）。SSd 组和 DXM 组之间无显著差异（p>0.05）。
本研究表明，SSd 可能通过抑制血管生成，下调 Ang/Tie2 通路中 ANG-1、Ang-2 和 Tie2 的表达，从而减少 BLM 诱导的小鼠肺炎症和 PF。
