The Observation Of Mifepristone On The Labor Induction Of Term Pregnant Rats And Its Effects On The Cerebral Tissue Of Mother Rats And Their Offsprings

Purpose: The recent and late effects of mifepristone on the cerebral ultrastructure of term pregnant rats and their offsprings were studied by the means of the TEM observation and stereolo- gical analysis. Methods: 25 pregnant rats were randomly divided into an experimental group (n1 3) and a control group (n=1 2), each group were further divided into a short term and a long term team. At the 20th day of gestation, the experimental rats were given mifespristone 11 .51mg and sesame oil lml, while the control rats were given only sesame oil 1 ml. Within 24 hours and ninty days post partum, the cortical tissues of the right parieto- cerebrum were respectively taken for the TEM observation and stereological analysis. Results: 1 For the short term team, compared with the control group, the mother rats of the experimental group showed the following morphological changes: (1) Neuron was edematous; (2) Major dense lines of myelin sheath were separated; (3) Synaptic con- nections decreased in number; (4) Interstitium was swollen. The cerebral tissue of the neonatal rats in the experimental group showed the following morphological changes: (1) Neuron was swollen or necrotic; (2) Neuropil was swollen and partially damaged; (3) Synaptic connections decreased in number; (4) Interstitium was edematous and the number of foamy cells increased. 2 For the long term team, compared with the control groups, the cerebral tissues of the mother rats and their mature offsprings in the experimental group had no morphological changes. 3 The results of the stereological analysis: (1) In the short term team: For the mother rats and neonatal rats, the numerical density of mitochondria of the control group in the partial end- ochylema of neuron were denser than that of the experiment group; the volume density of the control and the experimental group showed no significant change; the mean volume of the control group was distinctively smaller than that of the experimental group. (2) In the long term team, the neuron's numerical density of the cerebral cortex showed no significant difference between the control group and the experimental one. Conclusion: Mifespristone used for labor induction in the term pregna- ncy could make ischemia-hypoxia changes in the cerebral tiss- ues of mother and neonatal rats, but no distinguischable changes were found after ninty days.