Department of Medicine 1, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
Institute of Medical Biotechnology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany.
Inflamm Bowel Dis. 2022 Nov 2;28(11):1637-1646. doi: 10.1093/ibd/izac114.
Clinical challenges in inflammatory bowel diseases require microscopic in vivo evaluation of inflammation. Here, label-free imaging holds great potential, and recently, our group demonstrated the advantage of using in vivo multiphoton endomicroscopy for longitudinal animal studies. This article extends our previous work by in-depth analysis of label-free tissue features in common colitis models quantified by the multiphoton colitis score (MCS).
Fresh mucosal tissues were evaluated from acute and chronic dextran sulfate sodium (DSS), TNBS, oxazolone, and transfer colitis. Label-free imaging was performed by using second harmonic generation and natural autofluorescence. Morphological changes in mucosal crypts, collagen fibers, and cellularity in the stroma were analyzed and graded.
Our approach discriminated between healthy (mean MCS = 2.5) and inflamed tissue (mean MCS > 5) in all models, and the MCS was validated by hematoxylin and eosin scoring of the same samples (85.2% agreement). Moreover, specific characteristics of each phenotype were identified. While TNBS, oxazolone, and transfer colitis showed high cellularity in stroma, epithelial damage seemed specific for chronic, acute DSS and transfer colitis. Crypt deformations were mostly observed in acute DSS.
Quantification of label-free imaging is promising for in vivo endoscopy. In the future, this could be valuable for monitoring of inflammatory pathways in murine models, which is highly relevant for the development of new inflammatory bowel disease therapeutics.
炎症性肠病的临床挑战需要对炎症进行微观的体内评估。在这里，无标记成像具有巨大的潜力，最近，我们的小组展示了使用体内多光子内窥术进行纵向动物研究的优势。本文通过多光子结肠炎评分（MCS）对常见结肠炎模型中的无标记组织特征进行深入分析，扩展了我们之前的工作。
从急性和慢性葡聚糖硫酸钠（DSS）、TNBS、氧化偶氮甲烷和转移结肠炎的新鲜黏膜组织进行评估。通过二次谐波产生和天然自发荧光进行无标记成像。分析和分级黏膜隐窝、胶原纤维和基质细胞密度的形态变化。
我们的方法在所有模型中均能区分健康组织（平均 MCS=2.5）和炎症组织（平均 MCS＞5），并且通过对相同样本的苏木精和伊红染色评分验证了 MCS（85.2%的一致性）。此外，还确定了每种表型的特定特征。TNBS、氧化偶氮甲烷和转移结肠炎表现出基质中高细胞密度，而慢性、急性 DSS 和转移结肠炎的上皮损伤似乎具有特异性。隐窝畸形主要见于急性 DSS。
无标记成像的定量分析对体内内窥镜检查具有很大的前景。将来，这可能对监测小鼠模型中的炎症途径非常有价值，这对新的炎症性肠病治疗方法的开发具有重要意义。
