| Objective: To research the effects of early intervention on the expression of NB-3 and the change of cross-sectional area of myelin of white matter in brain injuried neonatal rat after intrauterine infection.Method: 1.Establishment of model and group: 60 Wister pregnant rats were randomly divided into two group: LPS group (n=45) and saline group (n=15).Pregnant rats were consecutively injected with LPS (380ug/kg) or saline on seventeen days gestation. The preterm rats whose gestation age was less than 22 days were removed in experiment. We selected arbitrarily neonatal rats (n=147) from LPS, divided into Intervention group (IA=93) and Non-intervention group (IB=49). Another NS group (II=54) from saline neonatal rats, Within 24 hours after birth, we choose 5 mice from LPS group and saline group, to detect pathology,respectively; at the same time, the uterus and placenta were taken out to be examined under microscope by the HE staining. 2. Early enriched environment interfere and rehabilition training: In IA group the second post-natal day of age (P2) rats were treated by early enriched environment till 14 days, from the beginning of 15 days, IA group were randomly divided into three groups: simple transcranial stimulation group,enriched rehabilitation training group,transcranial stimulation combined with enriched rehabilitation training group. Non-intervention group and control group was fed by routine way. we detect the expression of NB-3 at 1th,7th,14th,21th,28th and calculate the average myelin cross-sectional area of white matte at 14th,21th,28th by stereological method. 3. Adopting immunohistochemical characterization of experimental technique combined with image analysis techniques to detect the positive expression of brain NB-3 with the positive cell count and pictures were taken randomly at 8000 times and 15000 times in magnification transmission electron microscope. Application stereological techiques to measure and calculate the average myelin cross-sectional area of white matter of offspringResults: 1. offspring condition: The 15 normal saline pregnant rats delivered 120 full-term pups and none was died or pre-parturition; after LPS group were injected intraperi, 5 were dead and 3 ahead of delivery of 45 pregnant rats while the remaining 37 pregnant rats favorably deliver, 225 full- term pups and 35 were dead. 2. pathology testing: There were a large amount of neutrophilic granulocyte in the uterus and placenta in LPS-treated group; 1-day-old rat brain tissue pathology test showed: white matter of LPS group, corpus callosum, internal capsule parts organizations osteoporosis, Glial cells gathered, Capsule of oligodendrocyte reduction, and can also be found vasodilator, White matter capillary bleeding; there were no abnormal in NS group. 3. Stereology Results:①compared with 14 days, the cross-sectional area of myelin of II group at 21, 28 days increased by 23.7%, 41.7% (P <0.01).②at the 14 days, IB group's and IAgroup's cross-sectional area of myelin compared with II group's, there have significant difference. there has significant difference in IA and IB group(P<0.05).③at the 21,28 days,IA3 group's cross-sectional area of myelin compared with IA1,IA2,II group's, there have significant difference(P<0.05). II group's cross-sectional area of myelin compared with IA3, II group's cross-sectional area of myelin is higher than IA3, there have significant differences(P<0.05).IA1 group's compared with IA2 group's ,there have no differences(P>0.05). 4. To detect the expression of NB-3 in brain used by immunohistochemistry: with the increasing of days after birth, NB-3 positive cells gradually increased, at the 7 days after brith reach a peak, and later declined . 1-day-old, IA and IB group's expression of NB-3 higher than II group, the positive cell density higher (P<0.05);there were on differences between IA group and IB group(P﹥0.05);7-day-old,IA group's expression of NB-3 higher than IB group and II group, the positive cell density higher (P<0.05); 14-day-old,compared with IA group, IB group and II group's expression of NB-3 were lower(P<0.05); in the 21 days and 28 days, IA3 group's expression of NB-3 higher than IA1 group,IA2 group and IB group(P<0.05), IA1 group and IA 2group higher than IB group(P<0.05), there were on differences between IA1 group and IA2 group(P﹥0.05).Conclusion: 1.Intrauterine infection can reduce the cross-sectional area of myelin and increase expression of NB-3 in neonatal rats with brain injury; 2. Transcranial stimulation and enriched rehabilitated training and transcranial stimulation combined with enriched rehabilitated training can increase the expression of NB-3 and the cross-sectional area of myelin in neonatal rat with brain injury; 3. In terms of the therapy effection on brain damage induced by intrauterine infection, transcranial stimulation combined with enriched rehabilitation training is better than single transcranial stimulation or enriched rehabilitation training; 4. It is no correlation between the expression of NB-3 with the cross-sectional area of myelin of cerebral nerve myelin sheath in the brain of renascent rats. |
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