Effects of caspase-3 inhibitor on the neuronal apoptosis in rat cerebral cortex after ischemia-reperfusion injury / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the effect of z-DEVD-fmk, a caspase-3 inhibitor on the neuronal apoptosis in ischemia-reperfusion region (IRR) of rat cerebral cortex.</p><p><b>METHODS</b>Rats prepared by middle cerebral artery occlusion and reperfusion were used as the research model. The animals were divided into A group (untreated), B group (DMSO control) and C group (treated with z-DEVD-fmk). Before reperfusion, z-DEVD-fmk (7 microg/kg) was injected into the ischemic side of ventriculus cerebri of C group rats. The expression and activation of caspase-3, expression and cleavage of poly (ADP-ribose) polymerase (PARP), and apoptotic neurons in the temporal-parietal cortex IRRs (SPAB method) of all the rats were studied using Western blotting, in situ apoptotic detection (TUNEL method) and immunohistochemistry.</p><p><b>RESULTS</b>In the cerebral IRRs of A, B, C groups reperfused for 1 h and 24 h, the quantities of caspase-3 precursor were 16.7 +/- 3.0, 11.5 +/- 3.0 and 47.5 +/- 3.5, and 76.1 +/- 3.5, 71.3 +/- 6.4 and 88.2 +/- 5.5, respectively; the caspase-3 fragments (12,000) 8.2 +/- 2.3, 9.4 +/- 1.2 and 4.3 +/- 1.6, and 59.0 +/- 6.3, 60.5 +/- 7.2 and 17.3 +/- 2.8, respectively; the PARP 12.6 +/- 3.0, 13.9 +/- 2.0 and 53.7 +/- 4.1, and 67.5 +/- 8.6, 61.1 +/- 6.6 and 93.6 +/- 4.1, respectively; the PARP fragments (24,000) 6.0 +/- 0.7, 6.6 +/- 1.2, 3.6 +/- 1.1, and 27.4 +/- 2.6, 25.8 +/- 3.2, 12.1 +/- 2.8 (relative quantity, x+/- s); the densities of apoptotic neurons 83.3 +/- 7.5, 84.3 +/- 5.7 and 45.7 +/- 4.0, and 197.4 +/- 11.8, 185.2 +/- 11.2 and 99.1 +/- 5.8 (cell number/0.1 mm(2), x+/- s). These results showed that in the cerebral IRRs of both A and B groups, all caspase-3 expression and activation, PARP expression and cleavage, and neuronal apoptosis were increased relevantly along with prolongation of the reperfusion time (P < 0.05 - 0.001). At each time point of the reperfusion, caspase-3 activation, PARP cleavage and neuronal apoptosis in the cerebral IRR of C group were significantly less than those of the former two groups (P < 0.05 - 0.001). The variations of the 5 parameters of A, B and C groups correlated positively with one another (r = 0.630 - 0.942, P < 0.01). The cells expressing PARP were mainly neurons in the cerebral IRRs of all the animals, but the difference of their number was not distinct among the 3 groups.</p><p><b>CONCLUSIONS</b>It is an important mechanism resulting in apoptosis of the injured neurons in the cerebral IRR that caspase-3 expression and activation abnormally increased by the reperfusion have more PARP rapidly inactivated by over-cleavage. z-DEVD-fmk may decrease PARP cleavage by inhibiting activity and auto-activation of caspase-3, and prevent the injured neurons from apoptosis.</p>

Study on expression of ING1, human telomerase reverse transcriptase and telomerase-associated protein 1 genes in human gliomas / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between expressions of ING1 gene and genes of human telomerase reverse transcriptase (hTERT) and telomerase-associated protein 1 (hTP1) in human gliomas.</p><p><b>METHODS</b>The expressions of ING1 mRNA and p33(ING1) protein, hTERT mRNA and protein, and hTP1 mRNA and protein in seventy human glioma specimens with different malignant grades were studied using in situ hybridization and immunohistochemistry.</p><p><b>RESULTS</b>All of the 70 gliomas collected expressed hTP1 mRNA and protein and among them, 62 (88.6%) and 58 (82.9%) out of 70 expressed hTERT mRNA and protein respectively. The quantities of the four kinds of positive cells were correlated positively with one another (r = 0.758 - 0.882, P < 0.000 5), and all of them were significantly fewer in gliomas of WHO grade I - II than in grade III gliomas and the most in grade IV gliomas (P < 0.05 approximately 0.01). 66 (94.3%) and 62 (88.6%) out of 70 gliomas expressed ING1 mRNA and p33(ING1) protein respectively. The quantities of their positive cells were also correlated positively with each other (r = 0.831, P < 0.000 5), but the positive cells were more in gliomas of WHO grade I - II than in grade III gliomas and the fewest in grade IV gliomas (P < 0.01). The quantities of positive cells of ING1 mRNA and p33(ING1) protein were correlated negatively with those of hTERT mRNA and protein as well as hTP1 mRNA and protein respectively (r = -0.211 to -0.384, P < 0.05 approximately 0.001).</p><p><b>CONCLUSIONS</b>The results suggest that all of the parameters concerned are valuable in evaluating the biological behavior of gliomas. In glioma cells, overexpressions of hTERT and hTP1 genes might be significant in inhibiting the expression of ING1 gene. The abnormal expressions of the three genes play possibly the important roles in the development and malignant progression of gliomas.</p>