Journal of Capital Medical University ›› 2013, Vol. 34 ›› Issue (1): 58-63.doi: 10.3969/j.issn.1006-7795.2013.01.011

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Local mild hypothermia influences the expression of matrix metalloproteinase 9 and extracellular matrix proteins in a rat model of ischemia and reperfusion injury

LI Fang1,2, LIU Xiangrong2, YAN Feng2, ZHANG Chencheng2, LUO Yumin2, FANG Boyan3, JI Xunming2   

  1. 1. Postgraduate Institute of Liaoning Medical University, Jinzhou 121001, Liaoning Province, China;
    2. Cerebrovascular Diseases Research Institute, Xuanwu Hospital, Capital Medical University, Beijing 100053, China;
    3. Department of Neurology, Aerospace Center Hospital, Beijing 100049, China
  • Received:2012-10-18 Online:2013-02-21 Published:2013-02-25
  • Supported by:

    This study was supported by National Natural Science Foundation of China (81171241, 81200913).

Abstract:

Objective To investigate the effects of local mild hypothermia on expression of matrix metalloproteinase 9 (MMP9), extracellular matrix proteins laminin (LN) and fibronectin (FN) in a rat model of ischemia/reperfusion(I/R) injury. Methods Ischemia and reperfusion injury was produced in Sprague Dawley rats with modified suture-occlusion method. The ischemia caused by suture was persisted for two hours in the bodies of rat I/R injury models then the suture was removed. These I/R injury models were randomly assigned into the normothermia group and hypothermia group. Ice was placed under the heads of rats of the local hypothermia group and the cooling lasted for 1 h after reperfusion. Groups of normothermia and hypothermia were further divided into six subgroups with 4 h (N-4 h group and H-4 h group), 24 h (N-24 h group and H-24 h group), 72 h (N-72 h group and H-72 h group) of reperfusion, respectively. 2,3,5-triphenyltetrazolium chloride (TTC) staining was applied to measure the cerebral infarction volume, and the neurological deficits scores stood for the neurological function in N-24 h group and H-24 h group. Expression of MMP9, LN and FN were detected with immunofluorescence in ischemic penumbra of all groups. Results The percentage of cerebral infarction volume of H-24 h group was less than that of N-24 h group (P<0.01). Compared with N-24 h group, the neurological deficits scores of H-24 h group declined significantly (P<0.01). The expression of LN and FN of H-4 h group significantly increased versus N-4 h group (P<0.05). MMP9 reduced in the groups of H-4 h and H-24 h when matched with groups of N-4 h and N-24 h, respectively (P<0.05). ConclusionLocal mild hypothermia can significantly reduce the cerebral infarct volume and ameliorate the neurological dysfunction in rat I/R injury models. And it can diminish the expression of MMP9 and attenuate the loss of LN and FN. These findings indicated that MMP9, LN and FN may be involved in the protective mechanisms of the local hypothermia against cerebral ischemia/reperfusion injury.

Key words: cerebral ischemia/reperfusion, mild hypothermia, matrix metalloproteinase 9, laminin, fibronectin

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