| The vestibular sense to develop is second only to sense of touch during embryonicdevelopment, which is closely related to balance, motion, vision and audition. Developmentaldisorders of the vestibular system can lead to a balance and posture disturbance, sensoryintegration dysfunction and decline of learning ability. With the development of modernvehicle, as well as the improvement of living standards, the amount of gravida’s exercise hasreduced considerably. Epidemiological research showed that less exercise during pregnancymay be the main reason of hypertension, diabetes, and sensory integration dysfunction ofinfant. However, increased amount of exercise, such as swimming and dancing, may enhancethe ability of motor coordination and promote the development of central neural system andlearning ability. Recently, results have shown that hypergravity and microgravity environmentcan significantly change the developmental course of vestibular system, and remodeling thevestibular apparatus. However, only a few experiments were performed on animal vestibulardevelopment. Whether the exercise in normal gravity has effects on the functionaldevelopment of vestibular system remain blank.Our previous behavior results had shown that passive exercise during embryonicdevelopment period could improve the vestibular function of the fetal mouse significantly.And the best intervention period was the embryonic day from10to15(E10-E15), which wasstage of the vestibular organogenesis and the hair cell differentiated. However, whether theexercise during the critical period of embryonic development can promote the development ofvestibular nuclei and hair cells, as well as the molecular mechanisms awaits further study.In the present study, Kunming pregnant mouse were used as experimental animal,devided them into four groups: control group, restrict control group (restrict duringpregnancy), experiment group one (excercised in the critical period of embryonicdevelopment), experiment group two (restrict during pregnancy but exercised in the criticalperiod of embryonic development). Both experiment group one and two were exercised80minute everyday from E10to E15. The pregnant mouse’ food consumption and weight were examined. The number of fetal mouse and their survival rate, weight, the day of opening eyeand ear were detected. The behavioral method was used to detect vestibular function of fetalmouse. Using transmission electron microscopy technology, the development of vestibularhair cell of P0-P14mouse was investigated. The expression of Fos positive neurons in P7vestibular nuclei was detected by immunohistochemical methods. With these studies toascertain that whether the limited exercise during the embryonic period have effects on thedevelopment of vestibular function and the overall athletic ablility and vestibular hair cellmaturation were improved by exercise during the critical period of embryonic development.The results were as follows:1. The weight of pregnant mouse were not changed significantly, but exercise during thecritical period of embryonic development and limit exercise during pregnancy have an trendto decrease the weight of the pregnant mouse and increase their food consumption.2. There were no significant differences in the number, survival rate, the day of openingeye and ear of fetal mouse in different groups.3. At P0, the average weight of fetal mouse in restrict control group and experimentgroup two were lower than control group and experiment group one noticeably.4. The contact-righting rate of experiment group one was significantly higher than othergroups, also the time to complete contact-righting was significantly less than other groups.5. The developmental course of vestibular hair cell in fetal mouse were with nosignificance from P0to P14. Moreover, there were no significant differences in thedevelopmental course and the number of synapses of vestibular hair cell in fetal mouse, whichwere succeed and failed in contact-righting test.6. Fetal mouse in each group were observed more afferent nerve fibers coated with type Ihair cells at P2, which was earlier than other rodents.7. Given1.5h high intensity rotating stimulus to fetal mouse in P7, MVe, SpVe, X cellpopulations were activated but no significant differences were find in those groups.With the analysis on the experimental data, the results showed that:1. The restricted living space may lead to fear and anxiety, decrease of weight, andabnormal behavior (bite and desert the fetus when mouse delivery), but have no influence on the developmental course of fetal mouse. Therefor, the restrict method maybe not a good wayto esteblish the limited model.2. The vestibular function and athletic ability were significantly improved by exerciseduring the critical period in embryonic development, which confirm that E10-E15is thecritical period of exercise intervention.3. Not only exercise in critical period of embryonic development, but also restrictmovement during the whole embryonic stage, there were no significant differences in thedevelopment of vestibular hair cell and neurons.4. The innervation of type I hair cell in Kunming mouse maybe matured at P2, which isearlier than other rodents.In this study, these results provide some essential data to explore the effect of exercise onthe development of vestibular system. Our results may provide some theoretical foundation toguide the gravida’s exercise in gestational period. |
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