Effects of enriched environment on neural and ethological prognosis and contents of myelin basic protein of neonatal rats with hypoxic-ischemic brain damage / 中华实用儿科临床杂志

ABSTRACT

Objective To explore the impacts of enriched environment(EE),which has different initiation time points and intensity,on the neural and ethological prognosis and contents of myelin basic protein(MBP)of neo-natal rats with hypoxic - ischemic brain damage(HIBD). Methods HIBD rat models were established. Rats were divided into the early,the intermediate and the late intervention groups,which experienced EE from 7,14 and 21 days after HIBD for 14 days. The early and intermediate intervention groups were then divided into 6 - h and 24 - h groups, which experienced EE intervention for 6 hours or 24 hours respectively each day. Trapeze tests and water maze tests were carried out to detect the neural and ethological prognosis. Immunohistochemical method was used to detect MBP of the brain white matter,and the percentages of positive cells with MBP were detected by an image analyzer. The con-tents of MBP were measured. Results The trapeze test scores of the early and intermediate sham operation group,HI group,early 6 - h and 24 - h EE groups and the intermediate 6 - h and 24 - h EE groups,the late sham operation group,the late HI and late EE intervention group were(4. 05 ± 0. 88)scores,(2. 35 ± 1. 02)scores,(3. 67 ± 1. 12) scores,(3. 50 ± 1. 41)scores,(3. 50 ± 0. 93)scores,(3. 56 ± 1. 13)scores,(4. 00 ± 0. 89)scores,(2. 17 ± 1. 17)scores,(3. 50 ± 0. 92)scores,respectively. The trapeze test scores of early,intermediate and late EE groups were higher than those of the HI groups in the same period. There was no significant difference between the early,the intermediate 6 - h EE groups and 24 - h EE groups. Scores of water maze of each corresponding group were(40. 68 ± 23. 77)seconds,(56. 66 ± 10. 96)seconds,(46. 49 ± 19. 27)seconds,(51. 72 ± 20. 46)seconds,(38. 20 ± 18. 36)seconds,(47. 96 ± 20. 65)seconds,(38. 63 ± 20. 44)seconds,(59. 66 ± 13. 81)seconds and(45. 93 ± 22. 45)seconds,respectively. The water maze scores of the early,the intermediate 6 - h EE group and the late 24 -h EE groups were higher than those of the HI groups in the same period. There was no significant difference between the early,the intermediate 6 - h EE groups and the 24 - h EE groups. The relative abundance of MBP of the early and intermediate and the late HI groups were 6. 32 ± 1. 63 and 6. 74 ± 2. 19,and significantly less than that of the sham groups in the same periods,which were 9. 09 ± 1. 69 and 9. 37 ± 2. 46. The relative abundance of MBP of early 6 - h and 24 - h groups,the intermediate 6 - h and 24 - h groups and the late EE group was 7. 84 ± 2. 51,8. 05 ± 1. 86, 8. 89 ± 2. 29,8. 48 ± 2. 67 and 7. 98 ± 2. 09,respectively,which was significantly higher than that of the HI groups in the same periods. It showed that the neural and ethological prognosis of neonatal rats with HIBD could be improved,no matter the intervention began in the early,the intermediate or the late periods,or the intervention time was 6 hours or 24 hours each day. And relative abundance of MBP in the white matter increased with EE. Conclusions EE interven-tion has a long window stage for young rats. EE intervention could improve the neural and ethological prognosis of rats with HIBD. EE intervention could elevate the contents of MBP in the white matter,which could be one of the mecha-nisms for EE to improve the neural and ethological prognosis of rats with HIBD.