Glycosaminoglycan fractions in the organs of rats at single external x-ray exposure
Objective: To investigate the character of the changes in connective tissue GAG factions in the organs of rats at single external x-ray exposure at minimal and medial lethal doses. Material and Methods: The experiments were performed on 182 white male rats weighing 160-180 g. The animals were exposed to single total x-ray irradiation using РУМ-17 unit in standard conditions. Absorbed by the soft tissues doses were 4.0 and 6.2 Gy. Total and sulfated GAGs were extracted from the tissues using Clostridium Histoliticum hydrolysis (600 U) and precipitation with 2% cetylpyridinium chloride. GAGs were fractionated with ion-exchange chromatography on Dowex 1 x 2 with quantitative analysis of individual GAGs by the concentration of D-glucuronic and L-iduronic acids. The investigation was done on day 5, 7, and 14 and month 1, 3, and 6 after the radiation exposure. Age control was used at each term of the investigation. Statistical analysis of the obtained findings was done using Biostatistics v.4.03 for Windows. Results: It was established that the changes in GAGs and their fractions in the early post-radiation period and from day 3 to day 14 were characterized by increase of the level of total GAGs and hyaluronic acid fraction (hyaluronate) simultaneously in the lungs, on an average 1.5 and 1.9 times, and skin, on an average 1.4 and 1.8 times. In the long-term period, on month 3 and 6 after the exposure, regular changes of some fractions of sulfated GAGs depended on the tissue type. Tissue specificity of the changes in the fractions of individual sulfated GAGs in the long term period manifested in the lungs by increase of the level of chondroitin sulfates A and C 1.4 and 1.8 times on month 3 and 1.6 and 2.0 times on month 6 after the exposure and heparansulfate level in 1.2, 1.3 and 1.5, 1.7 times. Respectively, in the skin increase of the level of chondroitin sulfate B (dermatan sulfate) 1.6, 1.8 times and 1.7, 2.1 times and heparan sulfate 1.3, 1.4 times and 1.6, 1.9 times was observed. Conclusion: Single external x-ray exposure to minimal and median lethal doses causes stable increase of the total amount of GAGs and regular changes in their fraction composition in individual types of the connective tissue matrix of the lungs and the skin of the rats, which do not depend on the dose of irradiation but is tissue specific and depends on the time after the exposure.