3D Tissue Hepatocytes Culture Model Reflects The In Vivo Effects Of Fenofibrate

Hyperlipemia has become a common disease due to the greatly improved living condition. As hyperlipemia has been the major risk factor of atherosclerosis, people paid great attention to develop lipid-lowering drugs. Lipid metablism is mainly processed in liver where lipid lowering drugs regulate lipid metabolism and trigger hepatotoxicity. Therefore, liver is the focused organ to evualate the pharmacology and toxicity during the discovery process of lipid lowering drugs. As in vivo experiments on animals are often high cost and time-consuming, suitable in vitro models are urgently needed as a tool to screen lipid-lowering drugs in the early period of development. Currently, in vitro models of hepatocytes include sandwich, spheroids, monolayer culture and so on. But shortcomings can not be avoided in these models. For example, sandwich cultured hepatocytes lacks the structure of intercelluar junctions, while spheroid model is hard to prepare and poor reproducible. The monolayer culture model is widely used in the culture of hepatocytes in vitro. This model is easy to operate and has good repeatability. However, lipid metabolism in monolayer cultured hepatocytes is quite different from liver due to the lack of similar micro-environment in vivo. Moreover, monolayer cultured hepatocytes are not sensitive to the toxicity and effects of drugs. Nevertheless, gene expression related in lipid metabolism in monolayer and sandwich cultured liver cells is quite different from in vivo situation.In order to overcome the defects of monolayer model, gel-entrapment model was used to analyze the lipid metabolism, as well as the pharmacology and toxicity of a classical lipid-lowering drug—fenofibrate (FF) in this thesis. Micro-environment in gel-entrapped model is close to in vivo condition, and this model can maintain cell functions for a long time. This thesis verified the reliability of this model via comparison with the monolayer culture model and laid the groundwork for the pharmacology and toxicology evaluation of lipid-lowering drugs.First, lipid metabolism in both gel-entrapped and monolayer cultured hepatocytes were analyzed. The results showed that lipid metabolism in gel-entrapped hepatocytes is closer to liver which proves the reliability of this model to research lipid metabolism. Then the pharmacology of FF was researched in both monolayer and gel-entrapment models. The results showed that there was obvious lipid metabolism regulation effects in gel-entrapped hepatocytes which were not demonstrated in monolayer model. Subsequently, the short-term toxicity of fenofibrate was analyzed. Gel-entrapment model is more sensitive to the toxicity of fenofibrate and can reflect the in vivo toxic effects. By contrast, mono layer model failed to reflect the toxic effects of fenofibrate. At last, gel-entrapment model which can maintain the function of hepatocytes for a long period was used to investigate the long-term toxic effects of fenofibrate. Results showed that gel-entrapment model can reflect the pharmacology of FF and explain the toxic effects of it.In summary, the gel-entrapment model developed by our laboratory can be used to research the lipid metabolism, and the pharmacological mechanism of lipid-lowering drugs. The model also reflects the lipid-lowering drugs induced short-term and long-term toxicity. Thus, it has a good prospect in the screening, safety assessment and mechanism research of lipid-lowering drugs.