Ultrastructure of thyrocytes, assessment of their functional state after prolonged exposure to sodium benzoate and simulation of bone fractures and justification for the effectiveness of mexidol and selenase

Abstract

Aim – to study the effect of a 60-day exposure to sodium benzoate and a defect in the tibiae on the ultrastructure and functional state of rat’s thyroid gland thyrocytes and substantiate the effectiveness of mexidol and selenase. Material and methods. Eighty-four white rats were divided into seven groups. Animals of Group 1 and Group 2 were exposed to sodium benzoate at doses of 500 and 1000 mg/kg for 60 days, after which a through defect was applied in the tibiae. The rats of Groups 3-6 were additionally administered mexidol (50 mg/kg) or selenase (40 mcg/kg). In Group 7, saline solution was administered instead of sodium benzoate. The assessment of the functional state of thyrocytes was carried out on electronograms using a method developed by the author using a computer program. Results. In Group 1 and Group 2, the analysis of electronograms of thyrocytes revealed the predominance of inactive chromatin in the nucleus, expanded cisterns of the rough endoplasmic reticulum with fibrillar structures inside, a few secretory granules and short microvilli in the apical part of the cells, the presence of mitochondria with a destroyed matrix on 3rd day of observation. In Group 1, the functional state of thyrocytes corresponds to hypofunction on the 3rd day (15,80±0,20 points) and normal function on the 24th day (30,00±0,21), and in Group 2 – hypofunction in both periods (13,80±0,20 and 15,00±0,21). In Groups 3-5, the severity of electron microscopic changes in thyrocytes decreases and the functional state on 24th day corresponds to normal function, except for Group 6 (hypofunction (19,30±0,21 points)). Conclusion. Sixty-day administration of sodium benzoate and the creation of a defect in the tibiae are ultramicroscopically manifested by hypofunction of thyrocytes on the 3rd day, and by 24th day the functional state of the thyrocytes is replaced by normal function only in the group with the introduction of sodium benzoate at a dose of 500 mg/kg. The use of mexidol or selenase can reduce the severity of ultramicroscopic changes in thyrocytes and quickly restore their functional state.

Keywords

• thyroid gland
• thyrocytes
• ultrastructure
• functional state
• sodium benzoate
• mexidol
• selenase