Objective:To investigate the effects of propionic acid produced by Akkermansia muciniphila on the radiosensitivity of colorectal cancer and the underlying mechanism. Methods:Normal human colon mucosal epithelial cells (NCM460) were used to determine the appropriate concentration of propionic acid. Human colorectal cancer cells (HCT-8) were treated with A. muciniphila-conditioned medium or propionic acid, followed by exposure to 6 Gy γ-ray irradiation, and cell survival and proliferation were measured by clone formation assay and Cell Counting Kit-8 (CCK-8) assay, respectively. A mouse model of colorectal cancer was established using azoxymethane/dextran sodium sulfate. The mice were divided into control model group, irradiation group, and irradiation+ propionic acid group. Their body weight, colorectal length, tumor count, and tumor area were recorded. The radiosensitizing effect of propionic acid was assessed with HE staining, immunohistochemical staining, and enzyme-linked immunosorbent assay. The mechanism was explored by using RT-PCR and flow cytometry. Results:CCK-8 assay showed that 1-mmol/L propionic acid had no significant effect on the proliferation of NCM460 cells ( P>0.05), which was used for subsequent experiments. Pretreated with A. muciniphila-conditioned medium or propionic acid, the survival and proliferation abilities of irradiated HCT cells were significantly decreased ( t=3.14-34.98, P<0.05). Compared with the irradiation group, the colorectal cancer mice in the irradiation+ propionic acid group showed a significantly longer colorectal length ( t=3.50, P<0.05) and a significantly smaller number of tumors ( t=3.48, P<0.05); the two groups had significantly smaller tumor areas than the control model group ( t=5.97, 7.30, P<0.05). HE staining and immunohistochemical staining showed that propionic acid restored colorectal structure, and decreased Ki67 expression in colorectal tissue ( t=14.50, 3.40, P<0.05). Propionic acid treatment significantly reduced the levels of the inflammatory factors interleukin-6 and tumor necrosis factor-α, as compared with the mice receiving irradiation alone ( t=4.86, 5.06, P<0.05). Irradiation plus propionic acid treatment significantly increased p53 expression and significantly aggravated G 2/M phase block and cell apoptosis ( t=20.35, 13.05, P<0.05). Conclusions:The A. muciniphila metabolite propionic acid plays a sensitizing role in radiation therapy for colorectal cancer by promoting G 2/M phase block and apoptosis in colorectal cancer cells.

Objective:To investigate the effects of propionic acid produced by Akkermansia muciniphila on the radiosensitivity of colorectal cancer and the underlying mechanism. Methods:Normal human colon mucosal epithelial cells (NCM460) were used to determine the appropriate concentration of propionic acid. Human colorectal cancer cells (HCT-8) were treated with A. muciniphila-conditioned medium or propionic acid, followed by exposure to 6 Gy γ-ray irradiation, and cell survival and proliferation were measured by clone formation assay and Cell Counting Kit-8 (CCK-8) assay, respectively. A mouse model of colorectal cancer was established using azoxymethane/dextran sodium sulfate. The mice were divided into control model group, irradiation group, and irradiation+ propionic acid group. Their body weight, colorectal length, tumor count, and tumor area were recorded. The radiosensitizing effect of propionic acid was assessed with HE staining, immunohistochemical staining, and enzyme-linked immunosorbent assay. The mechanism was explored by using RT-PCR and flow cytometry. Results:CCK-8 assay showed that 1-mmol/L propionic acid had no significant effect on the proliferation of NCM460 cells ( P>0.05), which was used for subsequent experiments. Pretreated with A. muciniphila-conditioned medium or propionic acid, the survival and proliferation abilities of irradiated HCT cells were significantly decreased ( t=3.14-34.98, P<0.05). Compared with the irradiation group, the colorectal cancer mice in the irradiation+ propionic acid group showed a significantly longer colorectal length ( t=3.50, P<0.05) and a significantly smaller number of tumors ( t=3.48, P<0.05); the two groups had significantly smaller tumor areas than the control model group ( t=5.97, 7.30, P<0.05). HE staining and immunohistochemical staining showed that propionic acid restored colorectal structure, and decreased Ki67 expression in colorectal tissue ( t=14.50, 3.40, P<0.05). Propionic acid treatment significantly reduced the levels of the inflammatory factors interleukin-6 and tumor necrosis factor-α, as compared with the mice receiving irradiation alone ( t=4.86, 5.06, P<0.05). Irradiation plus propionic acid treatment significantly increased p53 expression and significantly aggravated G 2/M phase block and cell apoptosis ( t=20.35, 13.05, P<0.05). Conclusions:The A. muciniphila metabolite propionic acid plays a sensitizing role in radiation therapy for colorectal cancer by promoting G 2/M phase block and apoptosis in colorectal cancer cells.

Laboratory animals are the foundational conditions and indispensable technical support in life science research and biomedical industry development. The scientific development of animal models of diseases is of great significance to biomedical research and industrial development. In light of the booming development of multiple emerging in vitro modelling technologies over the past decade, in 2022, the U.S. Senate unanimously passed the bill FDA Modernization Act 2.0. This bill rescinded the requirement for animal testing in investigating the safety and effectiveness of a drug—a federal mandate since 1938, and highlighted the potential of various in vitro disease modeling approaches in future biomedical fields. This paper provides a comprehensive review of the latest advances and applications of in vitro disease modeling approaches in academia and industry followed by an interpretation of the FDA bill, namely cell culture, organoid, organ-on-a-chip, 3D bio-printing model and computer-based model. The paper next introduces the crossed applications of various disease models and discusses the advantages and disadvantages of each system, thereby providing insights into future trends in the use of animal disease models in China.

Objective: To evaluate the effect of venous anastomosis by using microvascular coupler during repair and reconstruction surgery after recection of tumor in oral and maxillofacial area. Methods: 20 patients with oral and maxillofacial tumor were chosen for repair of the defects via free flap. Microvascular coupler was applied to combine venous system,however,traditional methods were used in arterial anastomosis. Results: The average time of venous anastomosis using microvascular coupler was (5. 75 ± 0. 53) min,none of the cases were suffered from thrombosis after surgery. Vascular nerosis resulted from arterial spasm occured in 1 flap,reaching the flap survival rate of 95％(19 /20). Neck bleeding occurred in 1 case after surgery,the reflux of the anastomosed vein went smoothly when the blood clot was cleared,flap healing was unaffected. In another case,the coupler released during the surgery due to thick blood vessel wall as well as hypertension among the anastomotic edge,the vessels were manually sutured. Conclusion: With the appropriate indications, application of microvascular coupler may shorten the operating time,without affecting the effect of vascular anastomosis. The possibility of coupler loosing should be alarmed when bumped into great anastomotic tension or thick wall of the vein.