Isolation and culture of hepatic stellate cells.

Hepatic stellate cells (HSCs) are routinely prepared by collagenase/pronase digestion of liver using a perfusion system and subsequent fractionation of the heterogeneous cell suspension on continuous density gradients made out of Nycodenz, metrizamide, stractan, or percoll. Because of their lipid content, stellate cells are the least dense fraction of the nonparenchymal cells, and during centrifugation they float effectively away from other hepatic cells resulting in preparations containing almost 80% stellate cells. The degree of purity can be increased by further enrichment of cells by methods like centrifugal elutriation or Scatter-activated cell sorting. We present a detailed protocol from our laboratory to obtain a high number of pure, viable, freshly isolated hepatic stellate cells from rat liver. This two-step protocol (collagenase/pronase digestion and Nycodenz gradient) yields a preparation of approx 4-5 x 107 cells enriched in 74% HSC having a viability of at least 76% as estimated by Trypan blue exclusion test. Further purification by centrifugal elutriation results in virtually pure HSC preparations ( >98%).