Extracellular Matrix Metalloproteinase Inducer is Associated with Severity of Brain Oedema Following Experimental Subarachnoid Haemorrhage in Rats

OBJECTIVE: Brain oedema is a major cause of clinical deterioration and death following brain trauma; cellular mechanisms involved in its development remain elusive. This study investigated the role of extracellular matrix metalloproteinase inducer (EMMPRIN) in brain oedema. METHODS: The monofilament puncture model was used to induce subarachnoid haemorrhage. Adult male Sprague-Dawley rats were divided into five groups (n = 20 per group): sham-operated, sacrificed immediately after surgery (sham group); sacrificed 12, 24 or 72 h after subarachnoid haemorrhage induction (SAH-12, SAH-24 and SAH-72 groups, respectively); treated with EMMPRIN inhibitor immediately after subarachnoid haemorrhage, sacrificed at 24 h (SAH-inhibition group). Mean brain water content, and EMMPRIN mRNA and protein levels, were determined. RESULTS: Compared with the sham group, mean brain water content, EMMPRIN mRNA and protein levels in the SAH-12, SAH-24 and SAH-72 groups increased rapidly and significantly (maximal at 24 h). EMMPRIN inhibition significantly reduced mean brain water content and EMMPRIN mRNA and protein levels in the SAH-inhibition group, compared with the SAH-24 group. CONCLUSIONS: EMMPRIN upregulation may be important in the formation of brain oedema; inhibition of EMMPRIN activity may provide a potential approach to reduce oedema after subarachnoid haemorrhage.