HISTOLOGICAL STRUCTURE OF PROXIMAL METAPHYSEAL CARTILAGE OF HUMERUS IN RATS AFTER 60-DAY TARTRAZINE ADMINISTRATION
Belgorod, Russia The aim of the research is to study the histological structure of proximal metaphysial cartilage of the humerus in adult rats after 60 days of tartrazine administration (750 mg/kg and 1500 mg/kg body weight). Materials and Methods. The study was carried out on 90 white male rats, divided into 3 groups. In Group 1 (control), animals daily intragastrically received 1ml of0.9 % isotonic sodium chloride solution for 60 days. Rats of Groups 2 and Group 3 received intragastrically 1ml of tartrazine solution (750 mg/kg and 1500 mg/kg body weight respectively) for 60 days. The readaptation period after the last tartrazine administration was 3, 10, 15, 24, or 45 days. The area of the proximal humerus metaphysis underwent treatment according to the standard histological protocol. The obtained sections were stained with hematoxylin-eosin and subjected to a subsequent histomorphometric study. Results. On the 3<sup>rd</sup> day of the readaptation period, the total width of the proximal metaphysial cartilage of the humerus in animals of Group 2, was by 8.59 % less than the values of the control group; the width of the indifferent, proliferating and definitive cartilage was by 6.11 %, 8.85 % and 7.15 % less; the width of the destruction zone was by 11.55 % less; and the width of the osteogenesis zone was by 9.92 % less. The content of primary spongiosis in the osteogenesis zone and the number of cells on the trabeculae surface were lower than the values of Group 1 by 8.45 % and 8.42 % respectively. During the readaptation period, the authors observed similar dynamics of changes in the histomorphometric parameters of the metaphysical cartilage of the humerus with levelling by the 45<sup>th</sup> day of the experiment. In rats of Group 3, during the entire readaptation period, the histomorphometric parameters changed more significantly and their recovery to control values was slower than in animals of Group 2. Conclusion. 60-day tartrazine administration to adult rats is accompanied by inhibition of the bone formation function of the proximal metaphysial cartilage of the humerus. It is confirmed by a decrease in the width of all its zones and components of the osteogenesis zone. More pronounced in amplitude and duration changes in the parameters studied were recorded in animals treated with tartrazine, 1500 mg/kg body weight.