Effects of oxytetracycline on the mechanical properties of bone and skin in young rats.

The influence of the tetracycline antibiotics on growing bones has been disputed. In the present study 58 young male rats were given intraperitoneal injections twice a day for 2 weeks; half of the rats received oxytetracycline and the other half placebo. The concentration of oxytetracycline in plasma was comparable with therapeutic levels in man. Compared with the control animals the oxytetracycline rats had, at the end of the medication period, a significantly lower weight (7 per cent), shorter bones (1--2 per cent), lower bending strength of both the tibia diaphysis (9 per cent) and the distal femur metaphysis (22 per cent) and even lower tensile strength of intact (17 per cent ) and sutured (27 per cent) skin. The effect oxytetracycline seems to be reversible as no differences between the two groups could be detected 1--3 weeks after the end of medication.