THE STUDY OF INFLUENCE OF
Hypoxia-ischemia ON brain mitochondrial DNA in newborn piglets
Shi J, Yao YJ, Li WR
Second University Hospital, West China Medical
Center, Sichuan University, Chengdu, China
Objective: This study is to detect
the 8003 base pair (bp) fragmentation damage of brain mitochondrial DNA in
newborn piglets at different time after hypoxic-ischemic brain damage
(HIBD) so as to illuminate the biomolecular foundation of neonatal neuronal
metabolic disorder.
Methods: 3-day-age piglets (n=50)
were randomly divided into four experiment groups and a control group.
After the ligatation of the left common carotid artery, the experiment
groups were put into a container full of 8% O2 and 92% N2 for
2 hours to establish the HIBD animal model, and then exposed to normoxic
atmosphere for 0 hour, 24 hours, 48 hours and 72 hours respectively before
executed. Meanwhile sham surgeries were performed on the control group
which were exposed to normoxic atmosphere during the experimental period.
The left gerbil hippocampal cortex of all the groups were obtained to
amplify the fragments of 200bp and 8003 bp by LX-PCR method.The fragment of
200 bp was used to represent intra-contrast. We electrophoresed the PCR
products on agaros gels and took photoes at the UV light to get the
integral optical density (IOD).
Results: The IOD of 8003bp
fragment reduced dramatically in 0 hour post-hypoxic-ischemic (post-HI) group
(IOD=22.616+2.2759) when compared to that of control group
(IOD=56.975+0.3168, p<0.05).
It somewhat restored in 24 hours post-HI group (IOD=27.719+0.3091).
In 72 hours post-HI group, the IOD(54.972+2.2363) restored and
approached to the control value ( p>0.05).
Conclusion: The mitochondrial DNA of
the newborn piglet brain was fragmentated under the conditions of brain
hypoxia-ischemia .It would not recovered to normal untill 72 hours
post-HI.The fragmentation damage of mitochondrial DNA may be related
with depression of the
activity of mitochondrial respiratory enzyme and neuron apoptosis.