OBJECTIVETo investigate the influence of pleiotrophin (PTN) on the growth of rat hepatocytes.

METHODSPrimary rat hepatocytes were isolated from male Sprague-Dawley rats and divided into three groups: group A (negative control), cultivated in normal culture medium; group B (positive control), cultivated with culture medium supplemented with supernatant from the embryonic fibroblast 3T3 cell line; group C (experimental), cultivated with culture medium supplemented with human recombinant (hr) PTN (100 ng/ml). The hepatocytes' growth rate and level of secreted albumin (ALB) were evaluated by microscopy and biochemical assay, respectively. Significance of between-group differences were assessed by one-way ANOVA, and pairwise comparisons were performed by the least significant difference test.

RESULTSThe growth rates of hepatocytes in groups A, B and C were 2.800+/-0.084%, 4.300+/-0.132% and 3.800+/-0.053%, respectively. The growth rate of group B was significantly higher than the other two groups (F = 333.735, P less than 0.05). For all groups, the highest levels of secreted ALB were detected between the second and sixth day of culture, with g/L concentrations at day 2, 4 and 6 of: group A, 0.550+/-0.010, 0.900+/-0.030 and 0.300+/-0.040; group B, 0.900+/-0.030, 1.300+/-0.020 and 1.400+/-0.030; group C, 0.900+/-0.010, 1.160+/-0.010 and 0.700+/-0.050. The secreted ALB of group B was significantly higher than that of the other two groups (F = 651.355, 338.831 and 863.205, P less than 0.05 ).

CONCLUSIONPTN can benefit in vitro culturing of rat hepatocytes by stimulating growth and enhancing their ability to secrete albumin.