Botucatu Medical School, São Paulo State University, Brazil.
Department of Pathology, Ribeirão Preto Medical School, University of São Paulo, Brazil.
Histol Histopathol. 2020 Mar;35(3):289-301. doi: 10.14670/HH-18-152. Epub 2019 Jul 18.
The immunogenic collagen V (Col V) and the proinflammatory cytokine interleukin (IL)-17 have been implicated in the pathogenesis of multiple autoimmune diseases. Col V is also up-regulated during adipogenesis and can stimulate adipocyte differentiation in vitro. Conditioned medium (CM) generated from adipose-derived mesenchymal stem cells (MSCs) reduces bleomycin (BLM)-induced lung injury in rats, suggesting a crucial role in situ of immunomodulatory factors secreted by MSCs in these beneficial effects. In the present work, we investigated this hypothesis, analyzing levels of plasma inflammatory mediators and inflammatory and fibrotic mediators in the lung tissue of BLM-injured rats after treatment with MSCs and CM. Pulmonary fibrosis was intratracheally induced by BLM. After 10 days, BLM animals were further randomized into subgroups receiving saline, MSCs, or CM intravenously. On days 14 and 21, the animals were euthanized, and the lungs were examined through protein expression of nitric oxide synthase (NOS), IL-17, transforming growth factor-β (TGF-β), vascular endothelial growth factor, endothelin-1, and the immunogenic Col V through histological quantitative evaluation and plasma levels of fibrinogen, Von Willebrand factor, and platelet-derived growth factor (PDGF). Rats that had been injected with MSCs and CM showed a significant increase in weight and significant improvements at 14 and 21 days after intravenous injection at both time points of analysis of plasma fibrinogen, PDGF, and Von Willebrand factor and NOS-2 expression, supporting an early anti-inflammatory action, thus reducing TGF-β and collagen I fibers. In contrast, intravenous injection of CM was able to significantly increase the deposition of Col V fibers and IL-17 on both day 14 and day 21 as compared with the amount observed in rats from the BLM group and MSC groups. In conclusion, this study reinforces previous observations on the therapeutic properties of MSCs and CM and is the first report to demonstrate the association of its actions with immunomodulatory biomarkers on lung tissue. We concluded that adipose-derived stem cells and adipose-derived stem cells-CM modulate an in situ imbalance between collagen I- and Col V-mediated IL-17 immune response, emerging as a promising therapeutic option for recovering from BLM pulmonary fibrosis.
免疫原性胶原 V（Col V）和前炎性细胞因子白细胞介素 17（IL-17）已被牵连到多种自身免疫性疾病的发病机制中。Col V 在脂肪生成过程中也被上调，并可以在体外刺激脂肪细胞分化。脂肪来源的间充质干细胞（MSCs）产生的条件培养基（CM）可减少博来霉素（BLM）诱导的大鼠肺损伤，这表明 MSCs 分泌的免疫调节因子在这些有益作用中具有重要的原位作用。在本工作中，我们通过分析 BLM 损伤大鼠血浆炎性介质和肺组织中炎性和纤维性介质的水平，对这一假说进行了研究。通过 BLM 经气管内诱导肺纤维化。10 天后，BLM 动物进一步随机分为接受生理盐水、MSCs 或 CM 静脉内注射的亚组。在第 14 天和第 21 天，处死动物，通过肺组织中一氧化氮合酶（NOS）、IL-17、转化生长因子-β（TGF-β）、血管内皮生长因子、内皮素-1 和免疫原性 Col V 的蛋白表达，以及血浆纤维蛋白原、血管性血友病因子和血小板衍生生长因子（PDGF）的水平，对肺进行组织学定量评估。接受 MSCs 和 CM 注射的大鼠在静脉注射后第 14 天和第 21 天的体重显著增加，并且在两个分析时间点的血浆纤维蛋白原、PDGF 和血管性血友病因子和 NOS-2 表达方面均有显著改善，这支持了早期抗炎作用，从而减少 TGF-β 和胶原 I 纤维。相反，与 BLM 组和 MSC 组大鼠相比，CM 的静脉注射在第 14 天和第 21 天都能显著增加 Col V 纤维和 IL-17 的沉积。总之，本研究强化了先前关于 MSCs 和 CM 治疗特性的观察，并首次证明了其作用与肺组织中的免疫调节生物标志物有关。我们得出结论，脂肪来源的干细胞和脂肪来源的干细胞-CM 调节胶原 I 和 Col V 介导的白细胞介素 17 免疫反应之间的原位失衡，为从 BLM 肺纤维化中恢复提供了一种有前途的治疗选择。
