MICROSCOPIC EVALUATION OF EFFECTS OF SOME VITAL STAINING AGENTS ON GROWING BONE IN RABBITS

Various doses of alizarin red S, trypan blue, chlortetracycline and45Ca were injected into young male New Zealand white rabbits. The influence of these agents on bone growth was studied at the microscopic level by comparison with vital staining by lead acetate. From evaluation of bone growth on the basis of the distance between the lead acetate lines,45Ca had no adverse effect; temporary inhibition of bone growth was the largest with alizarin red S and least with chlortetracycline. The higher the average level of alizarin red S, trypan blue and chlortetracycline the stronger was the inhibitory influence on bone growth. Alizarin red S at 100 mg/kg reduced the rate of bone growth and at 150 mg/kg caused complete cessation of bone growth. Trypan blue at 100 mg/kg and 50 mg/kg of chlortetracycline caused a decrease in bone formation and 350 mg/kg of trypan blue stopped osteogenetic activity. The retardation by chlortetracycline was quickly overcome but after alizarin red S and trypan blue, normal bone growth was regained slowly. © 1968 Springer-Verlag.