增加高压氧疗程对治疗时间窗延迟的新生大鼠缺氧缺血性脑损伤的保护作用

Protective effects of delayed multiple course hyperbaric oxygen treatment against hypoxicischemic brain damage in neonatal rats

摘要:

目的：探讨多疗程的高压氧（HBO）治疗对96 h时间窗的缺氧缺血性脑损伤（HIBD）新生大鼠的保护作用。方法：7日龄Sprague-Dawley大鼠88只，随机分为正常对照组（CON）、HIBD组和HBO组。HBO组根据HBO治疗时间窗的不同分为2H，48H和96H组,即分别于HIBD后2，48 和96 h给予HBO；各亚组又根据不同疗程分成1疗程组（HBO-1）、2疗程(HBO-2) 和3疗程组 (HBO-3 )。HBO组（压力为2 ATA）每天给予HBO 1次，连续7 d为一疗程，休息3 d后进入下一疗程。各组待96H组的3疗程亚组完成全部疗程后，即鼠龄38 d （HIBD后31 d）时一同处死。采用TUNEL染色检测大脑皮层和海马CA1区神经细胞凋亡；并采用NSE免疫组化方法检测各组皮层神经元数量。结果：① HIBD组凋亡细胞数量明显高于CON组，同时NSE阳性细胞明显少于CON组（P<0.01）。② 随着治疗时间窗的延迟，单疗程HBO对凋亡的抑制作用及对神经元的保护作用逐渐减弱。③ 在48H和96H HBO组，HBO对神经细胞凋亡的抑制作用及对神经细胞的保护作用随着疗程的增加而逐渐增强；但2H HBO组经过一疗程HBO治疗后，凋亡细胞数量已经减少至CON组水平，而且NSE阳性细胞数量增加也接近CON组，随着疗程增加不再有明显变化。结论：① HIBD后2 h给予一疗程的HBO治疗即可明显抑制神经细胞的凋亡及保护神经元；② 增加疗程可增强治疗窗延迟的HBO对神经细胞凋亡的抑制与对神经元的保护作用。［中国当代儿科杂志，2009，11（6）：464-470］

Abstract:

OBJECTIVE: To study the protective effects of multiple course hyperbaric oxygen (HBO) treatment against hypoxic-ischemic brain damage (HIBD) in neonatal rats when HBO treatment is delayed (96 hrs after the HIBD event). METHODS: Eighty-eight 7-day-old Sprague-Dawley rat pups were randomly assigned to control, HIBD and HBO groups. The HBO group was subdivided into cohorts receiving treatment 2 h, 48 h and 96 h, respectively, after HIBD was induced. The three subgroups comprising different therapeutic windows were further randomly assigned to receive 1, 2 or 3 courses of HBO treatment ("HBO-1, -2 and -3 sub-groups"). HBO was administered once daily (2 ATA), a course lasting for seven days. There was an interval of three days between the courses. All pups were sacrificed at the end of HBO treatment (31 days after HIBD). TUNEL staining was used for testing neuronal apoptosis in the cortex and the CA1 of the hippocampus, and NSE staining was used to ascertain cortical neuronal population. RESULTS:① There were significantly more TUNEL positive cells in the HIBD group than in the control group; NSE positive cells were significantly lower than in controls (P<0.01). ② With the more delayed therapeutic window, the effects of apoptosis inhibition and neuronal protection of a single course of HBO were gradually reduced. ③ With increasing courses of HBO treatment, the effects of apoptosis inhibition and neuronal protection of HBO increased gradually in rats receiving treatment 48 and 96 hrs after HIBD. In the HBO group receiving treatment 2 hrs after HIBD, the number of apoptotic cells and NSE positive cells were close to that of the control group after one course of HBO treatment. CONCLUSIONS: One course of HBO administered within 2 hrs after HIBD can effectively inhibit neuron apoptosis and protect neurons. The effects of apoptosis inhibition and neuron protection of HBO can be increased through increasing the number of HBO treatment courses in neonatal rats with HIBD even if initiation of treatment is delayed after HIBD.［Chin J Contemp Pediatr, 2009, 11 (6):464-470］