Abstract
Human and gorilla dermal fibroblasts, primate cells, suspended in a collagen lattice, do not divide for the first 3 days. In contrast, rat fibroblasts divide within 24 hr. In this study, the proliferation of rat fibroblasts were compared to primate fibroblasts. Rat fibroblasts in monolayer culture increase from 100,000 to 355,000 in 2 days, and human cells increase from 100,000 to 436,000 in the same period. An initial seeding of 100,000 rat fibroblasts suspended in collagen increased to 163,000 cells in 2 days. An initial 100,000 human fibroblasts seeded in collagen decreased to 80,000 cells in 2 days. Retarded proliferation of human and gorilla fibroblasts in collagen is unrelated to a defect in DNA synthesis. By autoradiography human fibroblasts suspended in collagen incorporate labelled thymidine. By flow cytometry analysis, the DNA concentrations of human fibroblasts suspended in collagen exhibited 41% in a 4N chromosome state, compared to 14% in monolayer culture. Nuclei of gorilla fibroblasts from collagen displayed 42% in a 4N state, compared to 19% in monolayer culture. With nuclei of rat fibroblasts from collagen, 14% were in a 4N state, compared to 9% in monolayer culture. Primate fibroblasts show a three-fold increase in the number of nuclei in a 4N state compared to rat fibroblasts suspended in collagen. After replating fibroblasts released from collagen in monolayer culture in the presence of 1 mM hydroxyurea (an inhibitor of DNA synthesis) primate fibroblasts doubled in 24 hr. Under identical conditions, rat fibroblasts showed no cell division. Primate cells suspended in collagen have completed DNA synthesis but show a delay in cell division, indicating fibroblasts are arrested in G 2 of the cell cycle. Polymerized collagen produces a physical constraint on primate fibroblasts which retards these cells from entering mitosis. In contrast rat fibroblasts show no constraint and readily enter mitosis upon completion of DNA synthesis.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
