AIM To investigate the effect of
compound preparation of earth-worm and
leech on
cerebral ischemic tolerance in rat induced by focal ischemic preconditioning IPC and on
expression of matrix metalloproteinase-9 MMP-9 in
rats. METHODS The animal experiment was completed at the Surgery Laboratory of West China Hospital of Sichuan University from September 2004 to February 2005 and the imaging selection and analysis were completed in the Transplantation Immunity Center of West China Hospital from March to May 2005. ① Totally 48 healthy male SD rats were randomly divided into 3 groups sham operation group IPC group and IPC + compound preparation group with 16 in each group. The model of ischemic tolerance in rats was made by middle cerebral artery occlusion two times. IPC + compound preparation group After 10-minute IPC rats were injected intravenously with compound preparation of earth-worm and leech main component earth-worm leech and 1 g raw drug provided by Mudanjiang Youbo Pharmaceutical Limited-liability Company 2 mL/branch batch number 040413-1 10 mL/kg·d for 3 days. Then the animals were subjected to middle cerebral artery occlusion MCAO for 2 hours and reperfused for 22 hours. IPC group Rats were not treated with drug and other process was as the same as those in IPC + compound preparation group. Sham operation group Anatomic structure of rats was exposured but rats were not treated with 10-minute IPC and other process was as the same as those in IPC group. ② Eight rats from each group was waken for 2 hours and tested with neurological score 0-4 points 0 as without loss of neurological function 4 as unable to walking independently. ③ Five rats were selected from each group to obtain their brains to calculate the water content wet weight-dry weight/wet weight×100%. ④ Five rats were selected from each group to obtain their brains to make cerebral section to calculate infarct volume mm3 total of infarct volume of each layer × interval between layers. ⑤ Expressions of matrix metalloproteinase-9 in each group were compared with immunohistochemical staining and image analysis. ⑥ Measurement data were compared with analysis of variance. RESULTS One rat died in IPC group and IPC + compound preparation group respectively. After supplement 48 rats entered the final analysis. ① Neurological scores and water content Indexes in IPC group and IPC + compound preparation group were obviously lower than those in sham operation group neurological scores 2.01±0.21 1.76±0.36 2.31±0.68 points water content 82.01±0.83% 78.92±0.76% 85.23±1.08% P < 0.05 and those in IPC + compound preparation group was also lower than those in IPC group P < 0.05. ② Volume of cerebral infarction and expression of MMP-9 Values in IPC group and IPC + compound preparation group were obviously lower than those in sham operation group volume of cerebral infarction 142.79±17.84 103.00±12.46 198.32±19.56 mm3 expression of MMP-9 12 473.18±398.47 9 185.00±176.32 15 687.21±259.49 P < 0.05 and those in IPC + compound preparation group was also lower than those in IPC group P < 0.05. CONCLUSION IPC can induce cerebral ischemic tolerance and decrease of MMP-9 expression is possible one of mechanisms. Compound preparation of earth-worm and leech can down-regulate expression of MMP-9 further and relieve cerebral injury after ischemia which is of coincidence with IPC.
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