ABSORPTION OF CALCIUM IN SMALL INTESTINE OF RATS AFTER IMPACT OF VARIOUS XENOBIOTICS

Abstract

Relevance. Pathology of the thyroid and parathyroid glands, diseases of the digestive system, blood system, etc, as well as application of medications used for their treatment can result in the condition which is characterised by reduction of bone density – secondary osteoporosis. The aim of the research was to determine absorption of calcium in the small intestine of rats under impact of various xenobiotics. Materials and methods. The research was performed on white rats of herd breeding which, depending on the group obtained during 60 days: 1) cefoperazone (p/o, 180 mg/kg per day) and amoxiclav (p/o, 135 mg/kg per day); 2) mercazolil (p/o, 25 – 40 mg/kg per day); 3) L-thyroxine (p/o, 10 mg/kg per day); 4) hydrazine sulphate (50 mg/kg 2 times per week for 90 days). Calcium absorption was studied in an isolated loop of the small intestine of the animals. The condition of the small intestine mucous membrane was estimated in accordance with inflammation markers (elastate and acid phosphatase activity, index of the degree of opportunistic microbiota (urease activity), index of non-specific antimicrobial protection of mucous membranes (lysozyme activity). Long-term application of antibiotics contributed to reduction of calcium absorption in the small intestine of rats by 25.0 %, of mercazolil – by 29.7 %, of thyroxine – by 11.4 %, of hydrazine sulphate – by 34.5 %. The increase of elastase and acid phosphatase activity in the mucous membrane of the small intestine under the action of xenobiotics, as well as increase of urease activity and reduction of lysozyme activity testify to the change in the small intestine condition. Сonclusions. So, the significant reduction of calcium absorption after long-term application of xenobiotics can be first of all connected with inhibition of antimicrobial protection of the small intestine mucous membrane under the action of antibiotics, mercazolil, thyroxine and hydrazine sulphate. More active multiplication of opportunistic bacteria, presence of dysbiosis, and, after application of antibiotics and hydrazine sulphate, development of inflammation can be the consequence of lysozyme activity reduction.