Effects of extracellular matrix on rat Kupffer cell functions in vitro

Kupffer cells are known to play an important role in regulation of hepatocy te- and sinusoidal cell-functions in vitro. Thus, the modulation of Kupffer cells might contribute to the regulation of hepatocyte-functions in artifi cial organ of the liver as well as in vivo. In an attempt to clarify the in vivo function of sinusoidal cells for modulation of micro-organ of the liv er in vitro, Kupffer cell functions in different culture conditions have be en performed in the present study. Kupffer cells were prepared by perfusion/digestion of the liver with collag enase, followed by discontinuous centrifugation. Kupffer cells were culture d on non-coated plastic dish and MATRIGEL-coated dish. The morphological fe atures and phagocytic function of these cells were analysed by SEM and usin g 6.0 mu m diameter latex particles. In addition, TNF-alpha and NO producti on from the cells by stimulation of LPS as well as their transcriptional le vels were measured by ELISA, Griess reaction and competitive RT-PCR assey u sing mutant TNF-alpha mRNA and iNOS mRNA as internal standard, respectively . Kupffer cells cultured on plastic dish showed spindle protrusion and flare of cytoplasm, while the cells on MATRIGEL showed rounded shape with a minor protrusion of cytoplasm. Kupffer cells on plastic dish showed marked activ e phagocytic activity, while phagocytic activity was markedly reduced in th e cells on MATRIGEL-coated dish. Furthermore, an increase in TNF-alpha and NO production as well as transcriptional level of these biochemical substan ces were markedly enhanced in Kupffer cells on plastic dish when stimulated by LPS, while these enhancements were not demonstrated in the cells cultur ed on MATRIGEL-coated dish. These results suggest that Kupffer cell-functions in vivo might be differen t from those in vitro condition, and that the cells could be modulated by e xtracellular matrix(ECM). These data may suggest the reduced Kupffer cell f unction in case of liver cirrhosis. In addition, to regulate artificial org an of the liver, in vivo characterization of Kupffer cells should be needs further examination.