Functional study on two artificial liver bioreactors with collagen gel

Objective To improve the hollow fiber bioreactor of artificial liver. Methods Rat hepatocytes mixed with collagen solution were injected into the external cavity of a hollow fiber reactor to construct a bioreactor of hepatocytes suspended in collagen gel ( group Ⅰ) .Other rat hepatocytes suspended in solution were injected into the external cavity of a hollow fiber reactor with a layer of collagen on the wall of the external cavity to construct a bioreactor of collagen layer and hepatocytes ( group Ⅱ) . For each group, the culture solution circulated through the internal cavity of the hollow fiber bioreactor; the bioreactor was put in a culture box for 9 d, and the culture solution in the internal cavity was exchanged for new one every 24 h; the concentrations of albumin ( Alb) , urea, and lactate dehydrogenase ( LDH) in the culture solution samples were measured to examine the hepatocyte function of the bioreactor. Statistical analysis was performed using SPSS13. 0. Continuous data were expressed as mean ± SD, and comparison between groups was made by paired t test. Results For groups Ⅰand Ⅱ, Alb levels reached peak values on day 3 of culture ( 1. 41 ± 0. 08 g /L and 0. 65 ± 0. 05 g /L) ; from day 3 to 9, group I had a significantly higher Alb level than group Ⅱ ( t > 7. 572, P < 0. 01) . For groups Ⅰ and Ⅱ, urea levels reached peak values on days 3 and 5 of culture ( 1. 73 ± 0. 14 mmol /L and 1. 56 ± 0. 18 mmol /L) ; from days 5 to 9, group I had a significantly higher urea level than group Ⅱ ( t> 8. 418, P < 0. 01) . For groups Ⅰ and Ⅱ, LDH levels reached peak values on day 9 of culture ( 32. 03 ± 9. 13 U /L and 70. 17 ± 25. 28 U / L) ; from days 1 to 9, group I had a significantly lower LDH level than group Ⅱ ( t > 5. 633, P < 0. 01) . Therefore, the bioreactor of hepatocytes suspended in collagen gel ( group Ⅰ) showed a better hepatocyte function and less hepatic enzyme leakage compared with the bioreactor of collagen layer and hepatocytes ( group Ⅱ) . Conclusion Hepatocytes suspended and immobilized in collagen gel might be more suitable for construction of a hollow fiber bioreactor of artificial liver.