The Role of Herb-Partitioned Moxibustion in the Angiogenesis of Colitis-Associated Cancer in Rats.

Purpose: Angiogenesis in tumors is imperative to tumor growth. Our previous studies revealed that herb-partitioned moxibustion (HPM) could delay colitis-associated cancer (CAC), but the mechanism of the effects on the angiogenesis remains largely undiscovered. We aimed to investigate whether HPM delays CAC by inhibiting the angiogenesis with emergent three-dimensional (3D) imaging technologies.

Materials and methods: The CAC model was induced by azoxymethane (AOM)/dextran sodium sulphate (DSS). The rats were randomly divided into normal, model and HPM groups. The tumorigenesis, number of tumors, and tumor diameter were observed. Immunohistochemistry or enzyme-linked immunosorbent assay (ELISA) was performed to assess the microvessel density (MVD), reactive oxygen species (ROS), hypoxia-inducible factor-1 alpha (HIF-1α), vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 1 (VEGFR1), interleukin-6 (IL-6), interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α). The three-dimensional imaging of solvent-cleared organs with superior fluorescence-preserving capability (FDISCO) tissue clearing technique was used to clear colon tissues, and the platelet endothelial cells were stained and labelled with platelet endothelial cell adhesion molecule 1 (PECAM-1). Imaris software was used to perform 3D measurement and analysis of the colonic vascular architecture.

Results: The HPM group were found decreased in the colon tumor diameter, MVD, ROS, HIF-1α, VEGFA, VEGFR1, IL-6, IL-1β, and TNF-α in colon tissues compared with those in the model group. 3D imaging revealed that the number of vessels, number of branch points, and vessel branch level in the HPM group were lower than those in the model group. The number of branch points and vessel branch level were negatively correlated with the average vessel length.

Conclusion: HPM plays a role in inhibiting CAC angiogenesis. This study may provide new evidence at the macroscopic level of vascular architecture for HPM to inhibit the progression of CAC by FDISCO tissue clearing technique for 3D imaging.