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Int J Clin Exp Pathol 2013;6(1):66-75

Original Article
Effect of hyperbaric oxygen on neurological recovery of neonatal rats following hypoxic-
ischemic brain damage and its underlying mechanism

Xiaojuan Yin*, Fanping Meng*, Yu Wang*, Wei Wei, Aihua Li, Yannan Chai, Zhichun Feng

Affiliated Bayi Children’s Hospital, Beijing Military Region General Hospital, No 5, Nan Mencang, Dongcheng District, Beijing 100700, P.R.
China; Liver Cirrhosis Division, the No.302 Hospital of PLA, Beijing 100039, PR China. *Contributed equally.

Received September 12, 2012; Accepted October 25, 2012; Epub November 20, 2012; Published January 1, 2013

Abstract: Objective: To investigate the mechanism underlying the effect of hyperbaric oxygen (HBO) on hypoxic / ischemic brain damage (HIBD)
in a neonatal rat model. Methods: A total of 30 neonatal SD rats aged 7 days were randomly assigned into control group, HIBD group and HBO
group (n=10 per group). Following HIBD modeling in neonatal rats, HBO treatment was performed for consecutive 7 days.
Immunohistochemistry was done to measure the expression of bone morphogenetic protein-4 (BMP-4) and nestin in the hippocampus. In situ
hybridization was employed to detect the mRNA expression of BMP-4 and nestin in the hippocampus. TUNEL staining was done to detect the
apoptosis of nerve cells. Results: HIBD was successfully established in the present study. Among three groups, the protein expression of BMP-
4 in the hippocampus was the highest in the HBO group, and the smallest in the HIBD group. The BMP-4 expression in the HIBD group was
significantly lower than that in the control group. The protein expression of nestin in the hippocampus was the highest in the HBO group, and
the smallest in the HIBD group. The nestin protein expression in the hippocampus of HIBD group was significantly lower than that in the control
group. The mRNA expression of BMP-4 in the hippocampus was the highest in the HBO group, and the smallest in the HIBD group. The mRNA
expression of nestin in the hippocampus was the highest in the HBO group, and the smallest in the HIBD group. The number of apoptotic cells
was the largest in the HIBD group, and the number of apoptotic cells in the HBO group was still larger than that in the control group (P<0.01).
Conclusion: HBO may promote the neurological recovery in neonatal rats with HIBD, which may be attributed to the increased protein and
mRNA expression of BMP-4 and nestin in the hippocampus and the inhibition of neural apoptosis. (IJCP1209005).

Keywords: Neonatal rat, ischemic/hypoxic brain damage, hyperbaric oxygen, bone morphogenetic protein – 4, nestin

Address all correspondence to:
Dr. Zhichun Feng
Affiliated Bayi Children’s Hospital
Beijing Military Region General Hospital
No 5, Nan Mencang, Dongcheng District
Beijing 100700, PR China.
E-mail: drfengzc@fmmu.edu.cn