Bone Abstracts

Objectives: This study is aimed at investigating of histological features of mandibular condylar cartilage (MCC) in rats after 2-month inhalation of epichlorohydrin (ECh) vapors and administration of thiotriazoline (Th) and Echinaceae tinctura (ET) as medication.

Methods: The experiment involved 420 male rats (young, adult and senile). The animals were split into the groups: 1st group comprised control animals, the 2nd group comprised the animals that received inhalations of ECh in dosage of ten MPC as a single 5-hour exposure per day, 2nd group – inhalations of ECh and intraperitoneal Th in dosage of 117.4 mg per kg, 4th group – inhalations of ECh and intragastric ET in dosage of 0.1 mg of active substance per 100 g of body weight.

Results: In the study we found out that long-term inhalation of ECh (60-day daily 5-hour exposure to ten MPC) results in inhibition of morphofunctional activities (MFA) of the MCC. By the 1st day after ECh discontinue, width of subchondral osteogenesis zone (WSOZ), and amount of primary spongiosa (APS) and number of osteoblasts (NO) in it in young animals decreased in comparison with the control group by 11.33, 9.76 and 11.91% respectively; in adult animals the same values decreased by 11.14, 10.80 and 8.90%; in senile animals those values decreased by 9.07, 6.43 and 8.47% respectively. In readaptation period, in young rats inhibition of MFA of the MCC reduced by the 60th day and few significant changes were found after that term, in adult – alterations persisted up to the 30th day and then started reducing slowly, and in old – did not exhibit restoration signs. By the 60th day after ECh discontinue, WSOZ, and APS and NO in it in young rats decreased in comparison with the control – by 4.90, 3.61 and 3.86% respectively; in adult – the same values decreased by 4.64, 3.54 and 4.23%; in senile – those values decreased by 7.33, 5.90 and 7.50% respectively. In 3rd group restoration of MFA of the MCC in young and adult animals was observed from the 1st up to the 60th day, and in old – from the 7th up to the 60th day. In 4th group of MFA of the MCC in young animals was observed in the period from the 1st up to the 60th day, and in adult and old – from the 15th up to the 60th day of observation. Th thus appeared to be more effective than ET.

Conclusions: Application of Th or ET reduces negative effects of ECh on the MFA of the MCC. We proved Th to be more effective than ET.