The experiment was performed on 36 Wistar rats. On the first day of the experiment
iodoacetate was administered to the left posterior knee joint of the 18 rats
which composed Group I. The second group of 18 rats received additionally
doxycycline (doxy) through the gastric tube in doses comparable with those of
doxycycline used in humans. The experiment lasted 21 days. The animals were
sacrificed after 7, 14 and 21 days in groups of 6 rats each. In sections stained
with Safranin 0 semiquantitative histochemical intensity tests were performed
on articular cartilage glycosaminoglycans (GAG) using a four-point scale (0–3).
In the first group examined destructive lesions in the articular cartilage and weak
reactivity on GAG were noted at all stages of the experiment. The intensity of
GAG staining was higher in the second group after 14 and especially after 21 days,
which may suggest a protective action of doxy on articular cartilage
