Histamine affects growth of sheep ruminal epithelial cells kept in primary culture

Ten, 100 and 1000 microM histamine were applied to ruminal epithelial cells in primary culture. Each of these concentrations diminished cell count as well as the protein and DNA contents of cultures by approximately 20%. On Pappenheim staining, reduced cell count was predominantly attributable to a decrease in relatively chromophobic cells. It is concluded that histamine either induces apoptosis, or increases cell shedding, or interferes with mitosis and cell maturation. Each of these three possibilities implies that histamine may disturb epithelial regeneration after ruminal lactic acidosis.