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Neuroprotection of hypothermia combined with
salvia miltiorrhiza bunge on brain damage in the immature rat
abstract
Neonatal hypoxic-ischemia brain damage (HIBD) following perinatal asphyxia is one of most common disease, which leaded to newborn death and severly neurologic deficit of survivors. Mild hypothermia (28℃-35℃) can inhibit cell metabolism , the activation of enzyme and reduce free radical and delay neuronal apoptosis. Salvia miltiorrhiza bunge can clear out free radical and prevent lipid peroxidation and improve ATPase activies and protect respiratory chain basis function, go through microcirculation , promote blood circulation and immune regulative effect . In this study , we evaluted the effect of hypothermia and salvia miltiorrhiza bunge by the parameters of Maleic Dialdehyde and Superoxide Dismutase and nitric oxide in those postnatal 7-day rats’ brain tissue with HIBD ,hematoxylin and eosin (HE) staining.
Objective: 60 seven-day-old newborn Sprague-Dawley rats were randomized divided into groups : 1. sham operation. 2. hypoxic-ischemic . 3. salvia miltiorrhiza bunge (SMB) 4. hypothermia 5 . hypothermia combined with salvia miltiorrhiza bunge (HCS). Each group contained 12 rat pups. Randomly choose 2 pups from each group for pathologic section , the rest for determining MDA,SOD,NO.
Methods: 1. the preparation of HIBD model: At postnatal day 7, the pups were anesthetized by ether inhalation, then the left common carotid artery was ligated by double 4.0 lines. After surgical procedure, the pups were allowed to recover for 2 hours, then exposed to a gas mixture (8% oxygen in 92% nitrogen) for 2 hours. Sham operation group subjected to neither ligation nor hypoxia. 2. hypothermia: animals were placed in a stable water bath and the temperature can be adjusted according to the hypothermia protocol. 3. salvia miltiorrhiza bunge(SMB): after hypoxia, injected 10ml/kg salvia miltiorrhiza bunge by abdomenocentesis firstly, then 5ml/kg per 2 hour, 4 times altogether. 4. pathologic examination: pups were sacrificed 24h after hypoxia, the brains were dissected out and immersion-fixed in 10%paraformaldehyde, then dehydrated and paraffin embedded. Six coronal sections were stained with HE. 5. measurement of MDA、SOD、NO、 TISSUE PROTEIN. Details refer to specification. 6. statistical analysis: two way-ANOVA, q test were used in statistical analysis between groups. All the data expressed in the way of ±s were dealed with SPSS software. The significant different level was P<0.05 .
Results: 1. HE staining: compared with sham operation group, neuronal degeneration、edema and necrosis were found in HI group, the changes occurred less in HI and SMB, least in HCS . 2. Data of MDA、SOD、NO: MDA、NO decreased significantly in the hypothermia group and SMB , and SOD increased compared with HI, P<0.01 ; MDA、NO decreased in HCS, SOD increased compared with hypothermia group or SMB, P<0.05 ;there were no significant difference between group hypothermia and SMB.
Conclusion: Both hypothermia and salvia miltiorrhiza bunge therapy have protective effect on neuron, and HCS has better neuroprotection .
Key words: neonate rat , hypoxic-ischemic , brain damage, hypothermia, salvia miltiorrhiza bunge . |
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