Effect of thiram on chick chondrocytes in culture

The effect of thiram, a fungicide that increases the incidence of tibial dyschondroplasia (TD) in poultry, was studied in vitro using growth plate chondrocyte culture. Thiram caused a significant reduction in alkaline phosphatase, acid phosphatase, and lactate dehydrogenase (LDH) activities at concentrations of 5 microM and above. It was highly cytotoxic to chondrocytes at and above this concentration as determined by their ability to reduce 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (triazolyl blue, MTT), a marker of cellular viability. An increase in the leakage of LDH into culture media was evident at concentration as low as 1 microM. Very few differences were noticed in the electrophoretic migration profiles of cell-extract proteins at any treatment level relative to control. The cytotoxic effect of thiram is possibly due to its damaging effect on the cell membrane, which may be responsible for chondrocyte death.