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.

Albumins ; secretion ; Animals ; Carrier Proteins ; pharmacology ; Cells, Cultured ; Cytokines ; pharmacology ; Hepatocytes ; cytology ; drug effects ; secretion ; Male ; Rats ; Rats, Sprague-Dawley

Primary rat hepatocytes were cultured using different in vitro models and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH was decreased over time in culture. However, on day 5, LDH showed a significant increase in monolayer culture (MC) while after day 8 no LDH was detectable in sandwich culture (SC). The levels of AST and ALT did not change significantly over the investigated time. The CYP 1A activity was gradually decreased in a time-dependent manner in MC and SC. The decline of CYP 1A was faster in MC than in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducer such as Omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than in SC. In bioreactor basic CYP 1A activity was preserved over 2 weeks and the highest albumin production was observed in bioreactor followed by SC and MC. Taken together, it was indicated each investigated model had its advantages and disadvantages. It was also underlined that various in vitro models may address different questions.
Albumins ; secretion ; Animals ; Bioreactors ; Cell Culture Techniques ; methods ; Cell Separation ; Cytochrome P-450 CYP1A1 ; metabolism ; Hepatocytes ; cytology ; metabolism ; L-Lactate Dehydrogenase ; metabolism ; Male ; Mitochondria, Liver ; enzymology ; Mitochondrial Proteins ; metabolism ; Rats ; Rats, Sprague-Dawley ; Time Factors

Primary rat hepatocytes were cultured using different in vitro models and the enzyme leakage, albumin secretion, and cytochrome P450 1A (CYP 1A) activity were observed. The results showed that the level of LDH was decreased over time in culture. However, on day 5, LDH showed a significant increase in monolayer culture (MC) while after day 8 no LDH was detectable in sandwich culture (SC). The levels of AST and ALT did not change significantly over the investigated time. The CYP 1A activity was gradually decreased in a time-dependent manner in MC and SC. The decline of CYP 1A was faster in MC than in SC. This effect was partially reversed by using cytochrome P450 (CYP450) inducer such as Omeprazol and 3-methylcholanthrene (3-MC) and the CYP 1A induction was always higher in MC than in SC. In bioreactor basic CYP 1A activity was preserved over 2 weeks and the highest albumin production was observed in bioreactor followed by SC and MC. Taken together, it was indicated each investigated model had its advantages and disadvantages. It was also underlined that various in vitro models may address different questions.
Albumins/*secretion ; Bioreactors ; Cell Culture Techniques/*methods ; Cell Separation ; Cytochrome P-450 CYP1A1/metabolism ; Hepatocytes/*cytology ; Hepatocytes/metabolism ; L-Lactate Dehydrogenase/metabolism ; Mitochondria, Liver/enzymology ; Mitochondrial Proteins/metabolism ; Rats, Sprague-Dawley ; Time Factors