STRENGTH FEATURES OF RAT MANDIBLE AND HUMERUS AFTER LONG-TERM INFLUENCE OF TOLUENE VAPORS

Skorobogatov A. N., Gavrilov V. A.

CONTENTS

Scentific article

Aim was to determine strength features of mandibles and humeri after 60-day influence with toluene vapors and to assess possibility to correct adverse reactions with thiotriazoline and Echianceae tinctura. Materials and methods. The study involved 140 young male rats. The animals were distributed into the groups as follows; the first group comprised animals that received injections of isotonic solution of sodium chloride into peritoneal cavity, second group comprised the animals that received inhalations of toluene in the inhalation camera once a day in dosage of 10 MPC as a single 4-hour exposure, the third group comprised the animals that received daily intraperitoneal injections of 2. 5% thiotriazoline and toluene inhalations and the fourth group received per os Echinacaea tinctura in dosage of 1 mg of active component per 100 g of body weight. The strength parameters were determined by means of universal loading test device R-0. 5 at loading rate of 0. 25 mm per min up to destruction. From data obtained we calculated specific bending deflection, breaking point, elasticity modulus and minimum destruction work. Results and discussion. Inhalation of toluene resulted in decrease of bone strength. Thus specific bending de-flection values in humerus by the first day of observation period were higher than those of the controls by 15. 48% and fracture point, breaking point, elasticity modulus and minimum destruction work were lower as compared to controls by 11. 36%, 18. 50%, 17. 05% and 15. 97% respectively. In mandible specific bending deflection values were higher than those of the controls by 7. 68% and fracture point, breaking point, elasticity modulus and minimum destruction work were lower as compared to controls by 7. 53%, 14. 25%, 13. 13% and 8. 39%. In readaptation period changes in humerus persisted up to the 15th day of observation, namely specific bending deflection vales were higher than those of the controls by the 7th and the 15th days of observation by 11. 76% and 5. 35% respectively while fracture point, breaking point, elasticity modulus and minimum destruction work were lower as compared to controls by 9. 40% and 8. 57%, by 10. 31% and 8. 79%, and by 12. 23% and 9. 52% respectively. In mandible changes persisted up to the 30th day of observation. For instance, specific bending deflection values were higher than those of the controls in a period from the 7th to the 30th day of observation by 17. 13%, 10. 27% and 7. 67% respectively. Also, fracture point and elasticity modulus by the 7th and the 15th days of observation were lower by 11. 03% and 8. 11%, and by 16. 42% and 11. 09% respectively. For correction of adverse effects of toluene we selected thiotriazoline and Echinacaea tinctura. Injections of 2. 5% solution of thiotriazoline reduced adverse effects of toluene shown as return of strength parameters to baseline values. For instance values of the specific bending deflection in this case were lower than those of the group 2 (toluene exposure) by 8. 46% for humerus and by 7. 68% for mandible. Echinacaea tinctura had the same effects on both humerus and mandible yet its effects were less expressed that is thiotriazoline proved to be more effective than Echinacaea tinctura. Here values of the specific bending deflection in this case were lower than those of the group 2 by 5. 34% for humerus and by 7. 11%, 7. 12%, 492% and 4. 46% with respect to obser-vation terms (1st, 7th, 30th, and 60th days). Strength features changes of both humerus and mandible thus appeared to be uniform but in mandible changes amplitude and readaptation period length appear to be higher than those of the humerus. One can assume that it comes from morphological and functional features of the mandible i. e. mandible undergoes continuous dynamic mechanical load. Conclusions. Daily 60-day exposure to toluene affects bone strength of mandible and humerus. In readapta-tion period restoration of bone strength continued up to the 3oth day of observation. Thiotriazoline and Echinacaea tinctura reduced adverse effects of toluene on bone strength and thiotriazoline appeared to be more effective than-hinacaea tinctura.

lower jaw, humerus, strength, toluene, thiotriazoline, tincture of Echinacea purpurea

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«Bulletin of problems biology and medicine» Issue 2 part 2 (108), 2014 year, 138-141 pages, index UDK 591. 445:57. 044