Primary rat hepatocytes form spheroids on hepatocyte growth factor/heparin-immobilized collagen film and maintain high albumin production

We developed hepatocyte growth factor (HGF)/heparin-immobilized collagen film by adding HGF solution to collagen film, which immobilized heparin by chemical cross-linking. Primary rat hepatocytes maintained neither their specific morphology nor albumin synthesis on collagen film that directly immobilized HGF by cross-linking. By using HGF-supplemented medium, hepatocytes on collagen film formed typical monolayers and maintained albumin synthesis. Hepatocytes on HGF/heparin-immobilized collagen film formed spheroids after 3 days. They maintained albumin production during the culture period, the same as in HGF-supplemented medium. However, spheroids were not formed although the adhesion of hepatocytes was disturbed on heparin-immobilized collagen film, and albumin synthesis rapidly decreased during 5 days of culture. Because the mitochondrial activities of hepatocytes were not increased in all conditions, it was supposed that the cell proliferation did not occur. Therefore, it was shown that HGF/heparin-immobilized collagen film was effective for promotion of spheroid formation of hepatocytes and expression of their albumin production.