Effect of siRNA for mutant p53 gene on biological behavior of gastric cancer cell line SGC7901 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of silencing the expression of mutant p53 gene with RNA interference technique on biological behavior of gastric cancer SGC7901 cells.</p><p><b>METHODS</b>Recombinant plasmid of mutant p53 gene-targeting siRNA was transfected into gastric cancer SGC7901 cells by Lipofectamine(TM)2000. The expressions of mutant p53 gene mRNA and protein were identified by RT-PCR and Western blot assay. The proliferation of SGC7901 cells and changes of Oxaliplatin (OXA) drug sensitivity were detected by MTT assay. The cell cycle distribution and apoptosis rate were analyzed by flow cytometry. Changes in cell tumorigenicity ability were analyzed by colony formation assay and xenograft tumor formation in nude mice.</p><p><b>RESULTS</b>The expression of mutant p53 in SGC7901 cells was remarkable suppressed by mutant p53-siRNA. The cell growth curve of the transfected group turned to left compared to untransfected group and control group. The cell number of G(0)/G(1) phase of transfected group was decreased by 7.4% and 6.7% respectively, and that of S phase was increased both by 17.2% compared to control group and untransfected group, and the cell apoptosis rate induced by Oxaliplatin was remarkable decreased. The IC(50) of OXA in untransfected group, control group and transfected group were 15.88 μmol/L, 14.32 μmol/L and 20.34 μmol/L respectively. The colony formation rate and tumorigenicity ability in nude mice of transfected group increased remarkably.</p><p><b>CONCLUSION</b>Mutant p53-siRNA can significantly inhibit the expression of mutant p53 in SGC7901 cells, however, the use of RNA interference targeting mutant p53 gene in the treatment of gastric cancer is still uncertain.</p>

Relationship between inflammation and neointimal proliferation after coronary stent implantation in porcine model / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the relationship between inflammation and neointimal proliferation after coronary stent implantation in porcine model.</p><p><b>METHODS</b>Twenty normal minipigs were randomly divided into group A (implanted with 316L bare metal stents), group B (implanted with 605L bare metal stents), group C (implanted with PLGA coating 605L stents), and group D (implanted with rapamycin-loaded PLGA coating 605L stents). Each minipig was implanted with two same stents in left anterior descending artery and right coronary artery. Four weeks later, the animals were sacrificed and histomorphometric measurements on the stent-segment coronary arteries were made to calculate the correlation between inflammation area and neointimal area.</p><p><b>RESULTS</b>Group D had the smallest neointimal area [(0.64 +/- 0.38) mm2, P < 0. 001] and inflammation area (median 0.00 mm2, P = 0.009) among all the groups, while there were no statistical differences among group A, B, and C in neointimal area [(2.09 +/- 0.90), (2.11 +/- 1.07), and (1.42 +/- 0.35) mm2 respectively] and in inflammation area (0.22 , 0.21, and 0.09 mm2, respectively). Bivariate correlation analysis showed that the inflammation area was positively correlated with the neointimal area (P < 0.001, correlation coefficient = 0.719). When stent type, mean injury score, and EEL area were adjusted, partial correlations analysis showed that the inflammation area was still positively correlated with the neointimal area (P = 0.01, correlation coefficient = 0.498).</p><p><b>CONCLUSION</b>Inflammation promotes the neointimal proliferation after coronary stent implantation. Sirolimus-eluting stent may reduce the inflammatory response.</p>

Effects of atenolol and metoprolol on cardiomyocyte apoptosis and related gene expression after acute myocardial infarction in rats / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare the beneficial effects of Atenolol and Metoprolol on cardiomyocyte apoptosis and related gene expressions after acute myocardial infarction (AMI) in rats.</p><p><b>METHODS</b>AMI model was established with the ligation of anterior descending coronary artery in 251 randomly selected female SD rats. Twenty-four hours after operation, the 124 survivors were randomly assigned to AMI control group (MI group, n = 43), Atenolol group (group A, 10 mg x kg(-1) d(-1), n = 39), and Metoprolol group (group B, 20 mg x kg(-1) x d(-1), n = 42). Sham operation group (group S, n = 27) was also established. Two subgroup (48 h subgroup and 4 weeks subgroup) was randomly divided in each group according to the time points. Drugs were given to each treatment group by gastric gavage 24 h after ligation. Cardiomyocyte apoptosis was detected with terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) and DNA ladder. Bcl-2, bax and caspase-3 genes were detected with immunohistochemistry and Western blot analysis.</p><p><b>RESULTS</b>Compared with AMI control group, myocyte apoptosis rate (MAR) significantly decreased only in infarction area (P < 0.01) in group B. Bcl-2 expression was found to increase in myocytes of infarction, border and non-infarcted areas except for non-infarcted area of group A. Changes of the expressions of bax and caspase-3 was not significant. Four weeks after AMI, MAR was found to decrease significantly in scar, border and non-infarcted areas (P < 0.05, P < 0.01) in both group A and group B. No significant changes of bcl-2, bax and caspase-3 expressions was found except for a significant decrease of bax expression in non-infarcted area of group A. As indicated by Western blot, no significant change of the expressions of caspase-3, bcl-2 and bax were found in myocytes of group A and group B compared with AMI control group; however, bcl-2/bax ratio significantly increased to the same level of sham-operated group (P < 0.05).</p><p><b>CONCLUSION</b>Both Atenolol and Metoprolol treatment can reduce cardiomyocyte apoptosis in infarction/scar, border and non-infarcted areas after AMI, mainly through the increase of bcl-2 expression and bcl-2/bax ratio.</p>

Comparison of doxycycline, losartan, and their combination on the expression of matrix metalloproteinase, tissue inhibitor of matrix metalloproteinase, and collagen remodeling in the noninfarcted myocardium after acute myocardial infarction in rats / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare the effects of matrix metalloproteinase (MMP) inhibitor doxycycline, losartan, and their combination on the expression of MMP-8, 13, tissue inhibitor of MMP-1, 2 (TIMP-1, 2), and collagen remodeling in the noninfarcted myocardium after acute myocardial infarction (AMI) in rats.</p><p><b>METHODS</b>Two hundred and fifty-four AMI rats, induced by left coronary ligation, were randomly assigned to the following groups: (1) AMI controls group (n = 64); (2) doxycycline group (30 mg x kg(-1) x d(-1), n = 63); (3) losartan group (10 mg x kg(-1) x d(-1), n = 62); (4) concomitant doxycycline and losartan group (30 and 10 mg x kg(-1) x d(-1) respectively, n = 65); and (5) Sham-operated rats (n = 30), which were randomly selected to serve as noninfarction controls. Each group was further divided into three subgroups of 1, 2, and 4 weeks that received treatment. After the completion of treatment, the rats were killed. The mRNA and protein expression of MMPs and TIMPs in the noninfarcted myocardium were quantified by RT-PCR and Western blot, respectively. The type I and type III collagen volume fraction (CVF) of the noninfarced myocardium were assessed immunohistochemically.</p><p><b>RESULTS</b>No significant difference existed in myocardial infarction sizes among the 12 subgroups of AMI controls and the three treatment groups (42%-48%, all P > 0.05). Compared with sham operated rats, the mRNA and protein expression of MMP-8 and 13 significantly increased by 39%-183% in all three subgroups of AMI controls (all P < 0.05), except both of their mRNA expressions in 2-week subgroups; the mRNA and protein levels of TIMP-1 increased only in 1-week subgroup of AMI controls by 104% and 67%, respectively (both P < 0.05); the mRNA of TIMP-2 increased in all 1, 2, and 4-week subgroups by 144%-232% (all P < 0.05), but its protein expression lagged and only enhanced in 2 and 4-week subgroups of AMI controls by 231% and 332%, respectively (both P < 0.05). Meanwhile, both type I and type III CVF of noninfarcted myocardium significantly increased in all three subgroups of AMI controls (type I CVF: 3.01%-5.64% vs 1.53%-1.67%, P < 0.01-0.001; type III CVF: 2.19%-4.42% vs 1.46%-1.59%, P < 0.05-0.001), with type I CVF being higher in 4-week than in 1 and 2-week subgroups (5.64% vs 3.01% and 3.02% respectively, all P < 0.05). Compared with AMI controls, all three kinds of treatment significantly reduced the increased mRNA and protein expressions of MMP-8, 13 and TIMP-1, 2 after AMI by 14%-60% (all P < 0.05), as well as type I/III CVF in their 2 and 4-week subgroups (type I CVF: 1.56%-2.38% vs 3.02%-5.64%, P < 0.05-0.001; type III CVF: 1.92%-2.65% vs 4.19%-4.42%, P < 0.05-0.01), except for doxycycline's effect on type III CVF in any of its three subgroups (all P > 0.05). Among the three treatment groups, significant differences existed in the above mentioned indicators only at some subgroup levels (all P < 0.05).</p><p><b>CONCLUSIONS</b>Like losartan, doxycycline can also suppress the enhanced mRNA and protein expression of MMP-8, 13 and TIMP-1, 2, and reduce type I collagen deposition in the noninfarcted myocardium after AMI in rats. However, it has no effect on type III collagen deposition.</p>

Comparison of doxycycline, losartan, and their combination in the prevention of post-infarction remodeling in rats / 中国医学科学院学报

<p><b>OBJECTIVE</b>To compare the effects of doxycycline, losartan, and their combination in the prevention of left ventricular remodeling (LVRM) after acute myocardial infarction (AMI) in rats.</p><p><b>METHODS</b>Twenty-four hours after the induction of AMI, the 254 survival rats were randomly assigned to the following groups and received drug treatment: (1) AMI controls (n=64), (2) doxycycline (30 mg x kg(-1) x d(-1), n = 63), (3) losartan (10 mg x kg(-1) x d(-1), n = 62), and (4) combination doxycycline and losartan (30 and 10 mg x kg(-1) x d(-1) respectively, n = 65) treatment groups. Also, sham operated rats (n = 30) were selected randomly. Each group was further divided into three subgroups of 1, 2, and 4 weeks of treatment. After the completion of treatment, hemodynamic studies were performed. Then, the heart of rat was fixed and analyzed pathologically.</p><p><b>RESULTS</b>Exclusive of the dead rats and the hearts with the myocardial infarction size < 35% or > 50%, complete experimental data were obtained in 157 rats. Besides sham operated rats, there was no significant difference in myocardial infarction sizes among the 12 subgroups of AMI control and drug treatment groups (P> 0.05). Compared with sham operated rats, left ventricular end diastolic pressure (LVEDP) and left ventricular absolute weight and relative weight (LVAW and LVRW) were significantly increased in 1, 2, and 4 week subgroups of AMI controls (P < 0.05, P < 0.01, and P < 0.001, respectively), with LVEDP elevated more significantly in 4 week than in 1 and 2 week subgroups (P < 0.01); whereas the maximum rising and dropping rate of left ventricular pressure (+/-dp/dt) and its corrected value by left ventricular systolic pressure (+/-dp/dt/LVSP) were all significantly decreased only at 4 week subgroup of AMI controls (P < 0.001). Compared with AMI controls group, LVEDP was significantly decreased in all 1, 2, and 4 week subgroups of the three treatment groups (P < 0.05, P < 0.01, and P < 0.001, respectively); LVAW and LVRW were significantly decreased in 2 and 4 week subgroups of losartan and combination groups (P < 0.05, P < 0.01, P < 0.001, respectively), and in only 4 week subgroup in doxycycline (P < 0.05, P < 0.01, and P < 0.001, respectively); whereas the maximum dropping rate of left ventricular pressure and the corrected value of left ventricular pressure rising and dropping rate were significantly increased only in 4 week subgroups of all three treatment groups (P < 0.05, P < 0.01, respectively). There is no significant difference in all indices above among the three treatment groups at all three time points (P > 0.05).</p><p><b>CONCLUSION</b>It is indicated that doxycycline can prevent left ventricular remodeling and improve its systolic and diastolic function after AMI in rats, with the equivalent effect to that of losartan. There seems no additive effect when the two drugs are used in combination.</p>

Chronic sheep modal for pulmonary valve implantation with domestic bileaflet mechanical prosthesis / 中华外科杂志

<p><b>OBJECTIVE</b>The aim of this study was to identify the long-term character of the domestic bileaflet mechanical valve in the chronic implanted sheep model and to evaluate the potential value of the modal.</p><p><b>METHODS</b>Six adult sheep underwent implanted mechanical bileaflet valve in pulmonary position under the cardio-pulmonary bypass with beating heart. The chronic implanted sheep model was built up and observed in the respects of a long-term survival, function of prosthesis and pathological specimen.</p><p><b>RESULTS</b>Six adult sheep survived with good condition after operation. The average survival period of six sheep was (221 +/- 208) days. Two sheep were postoperatively sacrificed in 41 and 71 days, respectively. The necropsy revealed normal valve function without thrombosis, periprosthetic leakage and overgrowth of fibrous tissue. One sheep died from dysfunction of prosthetic valve at the postoperative 196 days. The reason was the prosthetic thrombosis with slight overgrowth of fibrous tissue in periprosthesis. The other two sheep died from severe anemia at the postoperative 196 days and 234 days, and the autopsy revealed no abnormal finding else. And one remained to survive with good condition up to now (over 617 days) and was checked by Doppler echocardiogram twice at the postoperative 438 days and 479 days, respectively. The results showed normal function of the bileaflet valve in pulmonary position.</p><p><b>CONCLUSION</b>The long-term good effects would be achieved by using the implanted new domestic bileaflet valve in pulmonary position of sheep.</p>