[Advantages of culture models utilizing substrata made of TOSHI (tissue/organ sections for histopathology) or collagen vitrigel membrane and their application concept for drug development researches].

To create new in vitro culture models for extrapolating the cell response in vivo, we attempted to devise culture substrata of anchorage-dependent cells. The first substratum, tissue/organ sections for histopathology(TOSHI)-substratum was found to conserve both tissue composition and microarchitecture in an in vivo environment. Collagen vitrigel membrane, the second substratum investigated, possesses excellent strength and protein permeability. Both substrata were developed and utilized for the culture of various anchorage-dependent cells. TOSHI-substratum prepared from regenerative mouse livers after carbon tetrachloride intoxication efficiently induced the differentiation of mouse embryonic stem cells into hepatocyte-like cells. Also, the time-course cell behavior of two different cell lines on various TOSHI-substrata prepared from rat mature organs was successfully converted into a three-dimensional graph chart, i.e. a mathematical model. These data suggest that the analysis of interactions between different cell types and various TOSHI-substrata will play an important role for a novel approach to study both cellomics and histomics. Meanwhile, the collagen vitrigel membrane is easy to handle by forceps, resulting in double surface-culture of different cell types by the manipulation of two-dimensional cultures. In the crosstalk model between PC-12 pheochromocytoma cells and L929 fibroblasts, nerve growth factor secreted from L929 cells permeated the collagen vitrigel membrane and induced neurite outgrowth of PC-12 cells via a paracrine effect. Futhermore, the function of rat primary hepatocytes was well maintained on the collagen vitrigel membrane. These data suggest that the collagen vitrigel membrane-substratum has many advantages for the reconstruction of culture models.