Yang Jinyou, Shimogonya Yuji, Ishikawa Takuji
Department of Biomedical Engineering, Graduate School of Biomedical Engineering, Tohoku University, 6-6-01 Aoba, Sendai 980-8579, Japan.
Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, 6-3 Aoba, Sendai 980-8578, Japan.
J Theor Biol. 2017 Apr 21;419:152-158. doi: 10.1016/j.jtbi.2017.02.004. Epub 2017 Feb 7.
Due to its transparency, the intestine of zebrafish larvae has been widely used in studies of gastrointestinal diseases and the microbial flora of the gut. However, transport phenomena in the intestine of zebrafish larvae have not been fully clarified. In this study, therefore, transport caused by peristaltic motion in the intestine of zebrafish larvae was investigated by numerical simulation. An anatomically realistic three-dimensional geometric model of the intestine at various times after feeding was constructed based on the experimental data of Field et al. (2009). The flow of digested chyme was analyzed using the governing equations of fluid mechanics, together with peristaltic motion and long-term contraction of the intestinal wall. The results showed that retrograde peristaltic motion was the main contributor to the mixing function. The dispersion caused by peristalsis over 30min was in the order of 10m/s, which is greater than the Brownian diffusion of a sphere of 0.4µm diameter. In contrast, anterograde peristaltic motion contributed mainly to the pumping function. The pressure decrease due to peristalsis was in the order of millipascals, which may reduce the activation and maintenance heat of intestinal muscle. These findings enhance our understanding of the mixing and pumping functions of the intestine of zebrafish larvae.
由于斑马鱼幼体肠道的透明度，其已被广泛应用于胃肠道疾病和肠道微生物群的研究中。然而，斑马鱼幼体肠道内的传输现象尚未完全阐明。因此，在本研究中，通过数值模拟研究了斑马鱼幼体肠道内由蠕动引起的传输。基于Field等人（2009年）的实验数据，构建了喂食后不同时间的肠道解剖学真实三维几何模型。利用流体力学控制方程，结合肠道壁的蠕动和长期收缩，分析了消化食糜的流动。结果表明，逆行蠕动是混合功能的主要贡献者。蠕动在30分钟内引起的扩散约为10米/秒，大于直径为0.4微米的球体的布朗扩散。相比之下，顺行蠕动主要对泵送功能有贡献。蠕动引起的压力降低约为毫帕斯卡，这可能会降低肠道肌肉的激活和维持热量。这些发现增进了我们对斑马鱼幼体肠道混合和泵送功能的理解。
