BIOMECHANICAL ANALYSIS OF CERVIX UTERI IN NONPREGNANT, PREGNANT AND ANTIGESTAGEN (ZK-98299) TREATED PREGNANT RATS

The biomechanical properties of the cervix uteri of the rat were studi ed under different pharmacological conditions. Four groups of rats wer e enrolled: A. non-pregnant (N = 12), B. 18 days pregnant treated with vehicle (N = 14), C. 18 days pregnant treated with the antigestagen Z K 98 299 (Onapristone(R)) for 19 hours (N = 15), D. 22 days pregnant d uring spontaneous labor (N = 12). Load-dimension curves of two 2 mm ri ng-preparations from each cervix were obtained by a material testing m achine. The results showed that the sampling position, the cervical ri pening process, and the influence of antigestagen treatment were refle cted in the biomechanical and compositional parameters. In conclusion the methodology in the present study constitute a model in which the e ffect of pharmaca on cervical ripening can be tested. The study demons trated that antigestagen treatment induced biomechanical changes in th e cervix comparable to those occurring during physiological cervical r ipening at term.