The Effect Of Matrix Metalloproteinase Inhibitor On The Apoptosis Of Diffuse Axonal Injuried Rats

Objectives: To detecting the apoptosis in rats' hippocampus and activity of matrix metalloproteinase with method of molecular biology (TUNEL) and gelatinase-zymography after diffuse axonal injury. Approach the relativity between matrix metalloproteinase activity and nerve cells' apoptosis.Methods: Sprauge-Dawley rats which weight from 250 to 350 grams were divided randomly into group experiment (group E, injected matrix metalloproteinase inhibiter-CTT into cerebral ventricle) and group contrast (group C, injected NS into cerebral ventricle). All rats in two groups had suffered from diffuse axonal injury after free-fall, and then these rats were allowed to survive for 30minutes, 1hour, 3hours, 6hours, 1day, 3days, and 7days. These brain injured rats then were executed at the time points above-mentioned. Compare the apoptosis in hippocampus by mean of TUNEL and activity of matrix metalloproteinase with gelatinasezymography.Results: 1 The population of apoptosis cell in group E were significantly less than that in group C(F=194.462 P＜0.01); activity of pre-enzyme MMP-9 in group E was significantly more than that in group C (F=1573.967 P＜0.01); there was no significant difference between group E and group C in the activity of pre-enzyme MMP-2; activity of active MMP-2 in group E was significantly less than group C(F=86.743 P＜0.01). 2 There is a negative correlation between apoptosis cells in brain of SD rats and the activity of pre-enzyme MMP-9 (0.85≤r≤1) at those time points after diffuse axonal injury; but positive correlation and the activity of active MMP-2 (0.55≤r≤1).Conclusions: 1 Population of apoptosis cell (from 30minutes to the third day), the activity of pre-enzyme MMP-2(from 30minutes to the seventh day), pre-enzyme MMP-9(from 30minutes to the first day) and active MMP-2 (from 30minutes to the seventh day)were progressing ascend in SD rats after diffuse axonal injury. 2 CTT can up regulation the activity of pre-enzyme MMP-9 and inhibit the activity of active MMP-2, but it has no significant effect on pre-enzyme MMP-2. 3 CTT can decrease the nerve cells' apoptosis of SD rats after diffuse axonal injury. It shows that CTT has some protections for the rats'diffuse axonal injury, and significantly degrade nerve cells from apoptosis.