Effects of tannic acid on liver function in a small hepatocyte–based detachable microfluidic platform

Tannic acid (TA) has been used to treat diarrhea, local skin burns, and rectal diseases and as a natural nonautogenous material in cell therapy. Since the ancient times, East Asian people have been drinking tea—rich in TA—to keep healthy, prevent cancer, and even protect liver from toxins. However, the mechanism underlying the hepatoprotective effects of TA warrants clarification. Here, we hypothesized that TA has effective hepatoprotective effects and created a novel, user-friendly liver-on-a-chip (LOC) platform by culturing rat small hepatocytes on a detachable microfluidic platform. This platform, which could mimic the liver microenvironment, was then used to determine the effects of TA on liver function. The results exhibited that (1) small hepatocyte have higher proliferation and differentiation capacity than that in mature hepatocytes; (2) after 7 and 10 days of TA-containing dynamic cultures, albumin synthesis and urea synthesis in small hepatocytes was 4 and 2 times higher than that in TA-containing static cultures, separately; (3) after 7 days of TA-containing dynamic cultures, albumin synthesis in small hepatocytes was 14 times higher than that in TA-free dynamic cultures. This result proved the current study that drinking tea can enhance health management. We also observed that liver function could be maintained for at least 2 weeks, indicating the applicability of our small hepatocyte–based LOC as an in vitro drug test platform.