[Effects of arsenic trioxide on human coronary smooth muscle cells: experiment in vitro].

OBJECTIVE: To study the apoptotic effects of arsenic trioxide on human coronary smooth muscle cells (HCSMCs). METHODS: HCSMCs were cultured and randomly divided into 5 groups to be treated by arsenic trioxide of the concentrations 1.0, 2.0, 3.0, 4.0, and 5.0 micromol/L for 48 h. Cell growth curve was drawn by MTT method. DNA electrophoresis was used to observe the apoptosis. Western blotting was conducted to examine the protein expression of Bax, an apoptosis-promoting gene, and Bcl-2, an apoptosis-inhibiting gene. Other HCSMCs were cultured with 4.0 micromol/L arsenic trioxide for 48 h, then transmission electron microscopy was used to observe the ultra-structure and TUNEL was used to detect the percentage of apoptotic cells. HCSMCs not treated with arsenic trioxide were used as control group. RESULTS: Arsenic trioxide of different concentrations inhibited the proliferation of HCSMCs dose and time-dependently. When the concentration of arsenic trioxide was 5.0 micromol/L the number of living cells was (4.41 +/- 0.10) x 10(5)/ml, significantly lower than that of the control group [(30.11 +/- 0.93) x 10(5)/ml, P < 0.05]. Apoptosis bodies were observed under the transmission electron microscope. DNA electrophoresis showed hazy ladders, especially when the concentrations were 3.0 - 4.0 micromol/L. When the concentration was 5.0 micromol/L the number of necrotic cells increased remarkably and apoptosis became less significant. TUNEL showed that the apoptotic cells increased from 16.0% +/- 3.1% to 38.7% +/- 2.7% (P < 0.05). MTT test showed that arsenic trioxide decreased the absorbance of HCSMCs dose and time-dependently. Western blotting showed that the Bcl-2 expression was decreased and the expression of Bax increased after treatment of arsenic trioxide. CONCLUSION: Arsenic trioxide exerts an apoptotic effect on HCSMCs.

[Relationship between plasma asymmetrical dimethylarginine and coronary artery disease].

OBJECTIVE: To investigate whether the plasma asymmetrical dimethylarginine (ADMA) level correlates with the extent and severity of coronary atherosclerosis. METHODS: 110 consecutive patients undergoing coronary angiography were divided into five groups according to the result thereof: control group (n = 22, with normal coronary artery), mild coronary artery disease (CAD) group (n = 21, with stenosis < 50% of the major coronary arteries), single branch CAD group III (n = 22, with stenosis >/= 50% of one major coronary artery); double branch CAD group IV (n = 23, with stenosis >/= 50% of two major coronary arteries); and multi-branch CAD group (n = 22, with significant stenosis >/= 50% of more than two major coronary arteries or companies with stenosis of left major coronary). ELISA was used to detect the plasma ADMA. Nitric acid reductase method and colorimetry were used to measure the levels of plasma nitric oxide (NO) and nitrogen oxide synthase (NOS). The relationship between the plasma ADMA and severity of CAD was analyzed. RESULTS: The plasma ADMA levels of in last three a groups were 1.52 micromol/L +/- 0.61 micromol/L, 1.67 micromol/L +/- 0.80 micromol/L, and 2.60 micromol/L +/- 0.62 micromol/L all significantly higher than that of the control group (0.79 micromol/L +/- 0.54 micromol/L, P < 0.01). The plasma NO and NOS levels of the multi-branch CAD group were significantly lower than those of the other groups (all P < 0.01), and there were not significant differences in Plasma NO and NOS levels among the other groups. Multivariate stepwise logistic regression analysis showed that the plasma ADMA level was significantly positively correlated with the severity of coronary atherosclerosis (r = 0.684, P = 0.007) and total cholesterol and triglyceride (r = 0.623 and 0.536 respectively), and significantly negatively correlated with the NO and NOS levels (r = -0.709 and -0.701 respectively). CONCLUSION: Correlated significantly with the severity of coronary atherosclerosis, the plasma ADMA level may become a novel marker of CAD.

[Expression of amyloid beta protein and amyloid precursor protein after focal brain ischemia in human].

OBJECTIVE: To observe the expression of amyloid beta precursor protein and amyloid beta protein in neurons of hippocampal CA1 region after brain ischemia in human. METHODS: Neuronal damage was examined by using HE staining, and expression of APP and Abeta(1-40) was determined by immunohistochemistry in the hippocampal CA1 region of the brain specimens of 43 patients who died 2 h-6 h, 7 h-24 h, 25 h-48 h, 49 h-72 h, 73 h-96 h, 97 h-144 h, or 145 h-168 h after cerebral ischemia and in 2 specimens of patients who died of other diseases as control group. RESULTS: The expression of Abeta(1-40) was 25.07 +/- 2.79 in the specimens 2 h-6 h after cerebral ischemia, peaked 73 h-96 h after cerebral ischemia (33.22 +/- 2.67), then decreased till 145 h-168 h after cerebral ischemia, however, all higher than that in the control group (2.88 +/- 0.18, all P < 0.05). The expression of beta-APP was 33.30 +/- 0.42 2 h-6 h after cerebral ischemia, was 28.11 +/- 2.03 7 h-24 h after cerebral ischemia, increased to peak value (32.32 +/- 1.36) 73 h-96 h after cerebral ischemia, and then decreased to 28.48 +/- 2.01, all higher than that of the control group (25.90 +/- 1.55) with significant differences between those 2 h-6 h and 73 h-96 h after ischemia and that of the control group (both P < 0.01). The increase of beta-APP was positively correlated with the expression of Abeta(1-40) 24 h after ischemia. CONCLUSION: The expression of beta-APP and that of Abeta(1-40) are up-regulated after cerebral ischemia, thus aggravating cerebral ischemia.

[Effect of arsenic trioxide on rabbit vascular smooth muscle cells after balloon angioplasty].

OBJECTIVE: To study the apoptotic effect of arsenic trioxide on rabbit vascular smooth muscle cells (RVSMCs) after balloon angioplasty. METHODS: A New Zealand rabbit underwent balloon angioplasty three times at one of its iliac arteries. The iliac artery at the opposite side was used as control. Three days after the rabbit was killed. The VSMCs of the iliac artery undergoing balloon angioplasty were cultured. Arsenic trioxide of different concentrations was added into the culture. VSMCs not co-incubated with arsenic trioxide was used as controls. Cell proliferation curve was drawn. DNA was extracted and underwent electrophoresis. Transmission electron microscopy was used to observe the ultramicroscopic structure. TUNEL technique was used to examine the apoptosis of cells. RESULTS: Cell proliferation curve showed that the control cells grew geometrically and reached a plateau stage by day 3. The cells co-incubated with arsenic trioxide proliferated more slowly and the plateau stage appeared earlier dose-dependently (P < 0.05). Electrophoresis showed obscure ladder band of DNA specific to cell apoptosis, especially at the concentrations of arsenic trioxide of 3.0 and 4.0 micro mol/L. Transmission electron microscopy showed apoptotic cells with apoptosis nodes. TUNEL technique showed that the number of yellow-dyed cells was significantly larger after the addition of arsenic trioxide. The above-mentioned manifestations were not seen in the control group. CONCLUSION: Arsenic trioxide increases the apoptosis of rabbit vascular smooth muscle cells after balloon angioplasty and inhibits RVSMCs over-proliferation. It is a hopeful measure in prevention of re-stenosis after angioplasty.