| [objective] the present study was designed to investigate the expressions and possible roles of matrix metalloproteinase-2, -9 mRNA after hypoxia-ischemia brain damage in perinatal sprague-dawley rats and in cultured cortex nerve cells on the condition of hypoxi a. [methodsl (-) By performing a delayed cesarean section on pregnant Sprague-dawley rats, a experimental model to produce general asphyxia is presented, which result in asphyctic damage to the brains of newborns. all the animals were divided into four groups: hypoxi a-ischemia for 10 minutes group, hypoxia-ischemia for 20 minutes group, self-control group and control group. 811 m coronal brain cryo-section through the optic chiasma and the choana in brain abdomen-side were made. By means of hybridization in situ, the expressions of MMP-2 mRNA^ MMP-9 mRNA were investigated at individual time point designed as 0 hour, 8 hours, 24 hours, 48 hours and 72 hours after hypoxia-ischemia brain damage in perinatal sprague-dawleyrats. () a anoxic experiment mode of cultured cortex nerve cellsat seventh day in vitro formed -by overjetting liquid paraffin to culture medium and persisting it for 72 hours was presented, then the expressions of MMP-2mRNA^ MMP-9mRNA were observed at the cortex nerve cells of the anoxia group and the control proup which didn' t go through the hypoxia.[results] (? the stain of hybridization in situ for MMP-2mRNA and MMP-9mRNA: (1) control group: from 0 hour to 72 hour after cerebral hypoxia-ischemia at pregnant Sprague-dawley rats, no MMP-9mRNA expression was found at rat brain of control group; whereas the expression of MMP-2mRNA was identified faintly and contitutivelly in all the time points' rat brains. (2) self-control group: the positive stain of MMP-9mRNA was detected and located in hippocampi and dorsal thalamus at 8 hours after the cerebral hypoxia-ischemia, but the signal was weak, the expression of MMP-2mRNA was no change comparable with the control group. (3) hypoxia-ischemia for 10 minutes group , 20 minutes group: our experiment showed that at 24 hours after cerebral hypoxia-ischemia, expression of MMP-9mRNA was maximally increased, individually, in the hypoxia-ischemia for 10 minutes group, MMP-9mRNA was greatly expressed within superolateral surface cortex of cerebrum, whereas in the hypoxia-ischemia for 20 minutes group, the labeling of hybridization for MMP-9mRNA was strongly appeared within the cortexof cerebrum both the cortex in the subsequence of medial surface at the periphery of the cerebral longigudinal fissure and the cortex in superolateral surface where also there showed a few stained fibers. At 48 hours after cerebral hypoxia-ischemia, the MMP-9mRNA expression slightly decrease but still appeared significantly. In the hypoxia-ischemia for 10 minutes group, MMP-9mRNA expression was identified within local lateral surface cortex of cerebrum; whereas in the hypoxia-ischemia for 20 minutes group, the strongly positive stain of MMP-9mRNA was located in lateral surface cortex of cerebrum and hippocampi, especially in CAS region, a few cells in the nucleus caudatus putamen also appeared with positive stain of MMP-9MRNA. At 72 hours after cerebral hypoxia-ischemia, MMP-9mRNA was still expressed massively in hippocampi and lateral surface cortex of cerebrum in which the labeling of MMP-9mRNA was associated with a great many fibers. On the other hand, after cerebral hypoxia-ischemia, MMP-2mRNA was not observed significant increase. in the hypoxia-ischemia for 10 minutes group, the stained cells was found especially in CAS region of hippocampi. Whereas in the hypixia-ischemia for 20 minutes group, Some section was found MMP-2mRNA-labeled cells in all the regions of hippocampi. (H) the cultured cortex nerve cells in vitro, both the anoxic group and the control group, not showed MMP-2mRNA, MMP-9mRNA expression aftercultured for 72 hours under the condition of hypoxia.[Conclusions! our experiments showed a time-dependency expression for MMP-9mRNA after hypoxia-ischemia brain damage in pe...
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