ABSTRACT
<p><b>OBJECTIVE</b>To observe the changes of nuclear factor-kappa B (NF-kappaB) in the course of N-methyl-N-nitrosourea (MNU)-induced apoptosis of rat retinal photoreceptor cells and investigate the mechanism of MNU-induced retinal damage.</p><p><b>METHODS</b>A single intraperitoneal injection of 60 mg/kg MNU was given to 50-day-old female rats, which were sacrificed at different intervals after MNU treatment. The retinal damage was examined with optical microscopy and photoreceptor cell apoptosis detected by TUNEL assay. Western blotting was performed to analyze the changes in NF-kappaB.</p><p><b>RESULTS</b>Pyknosis of the photoreceptor cell nuclei and disorientation of the outer segment of the photoreceptor layer was observed 24 h after MNU treatment, and the outer nuclear layer and photoreceptor layer were almost completely lost on day 7. Photoreceptor cell apoptosis peaked at 24 h, and in the apoptotic cascade, NF-kappaB p65 protein was only detected 12 and 24 h after MNU treatment, whereas the amount of I kappa B alpha, in contrast, markedly increased in the cytoplasm as well as in the nuclei.</p><p><b>CONCLUSION</b>MNU-induced retinal damage might be mediated through the signaling pathway of NF-kappaB/I kappa B alpha.</p>
Subject(s)
Animals , Female , Rats , Apoptosis , Blotting, Western , I-kappa B Proteins , Metabolism , In Situ Nick-End Labeling , Methylnitrosourea , Toxicity , NF-kappa B , Metabolism , Rats, Sprague-Dawley , Retinal Diseases , Metabolism , PathologyABSTRACT
<p><b>BACKGROUND</b>Previous studies have showed that photooxidative stress can lead to down-modulation of nuclear factor-kappa B (NF-kappaB) activity causing apoptosis of cultured photoreceptor cells. This study aimed at investigating whether NF-kappaB was involved in photoreceptor cells apoptosis induced by N-methyl-N-nitrosourea (MNU) in rats.</p><p><b>METHODS</b>A single intraperitoneal injection of 60 mg/kg MNU was given to 50-day-old female rats. At different intervals after MNU treatment, the animals were sacrificed. Retinal damage was examined by a light microscope. The apoptotic index of the photoreceptor cells was detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL). NF-kappaB was analysed by Western blot and Transcriptin Factor Assay Kits.</p><p><b>RESULTS</b>The pyknosis of the photoreceptor nuclei and the disorientation of the outer segment of the photoreceptor layer was seen after MNU treatment for 24 hours. The outer nuclear layer and photoreceptor layer were almost completely lost at 7 days. Photoreceptor cells apoptosis reached the peaked value at 24 hours. In apoptotic cascade, the protein levels of NF-kappaB p65 were only detected after MNU treatment for 12 and 24 hours in the nucleus. Conversely, the amounts of IkappaBalpha were markedly increased in the cytoplasm as well as in the nucleus. The activity of NF-kappaB p65 in the nucleus was down-modulated in the end.</p><p><b>CONCLUSIONS</b>MNU-induced photoreceptor cell destruction was attributed to the apoptotic process by down-regulating the activation of NF-kappaB p65.</p>
Subject(s)
Animals , Female , Rats , Apoptosis , Cell Nucleus , Metabolism , I-kappa B Proteins , Physiology , Methylnitrosourea , Toxicity , NF-KappaB Inhibitor alpha , NF-kappa B , Physiology , Photoreceptor Cells , Chemistry , Pathology , Rats, Sprague-Dawley , Retina , PathologyABSTRACT
<p><b>AIM</b>To study the effect of non-mitogenic human acidic fibroblast growth factor (nm-haFGF) on retinal injury induced by N-methyl-N-nitrosourea (MNU) in Sprague-Dawley rats and its mechanism.</p><p><b>METHODS</b>Female rats of 50-days-old were injected with MNU (60 mg x kg(-1)) intraperitoneally, and three doses of nm-haFGF (1.25 microg, 2.5 microg and 5 microg in one eye of each rat) were injected, separately, into vitreous body of one eye of each rat twice a day at 0 and 12 h after MNU treatment. 24 h later, apoptotic index of photoreceptor cells was detected by TUNEL labeling and the expressions of Bcl-2 and Bax were analyzed by Western blotting. At the 7th day, retinal injury was evaluated based on retinal thickness.</p><p><b>RESULTS</b>Compared with model group, apoptotic index of photoreceptor cells was significantly reduced in nm-haFGF groups at the dose of 1.25 microg and 2.5 microg in one eye of each rat at 24 h, and the total retinal thickness as well as the outer retinal thickness markedly increased 7 days after MNU, respectively. The expressions of Bcl-2 increased and that of Bax decreased adversely after being injected with different doses of nm-haFGF.</p><p><b>CONCLUSION</b>nm-haFGF partially suppressed retinal injury induced by MNU in Sprague-Dawley rats. The mechanism could be related to up-regulation of Bcl-2 and down-regulation of Bax.</p>
Subject(s)
Animals , Female , Rats , Apoptosis , Fibroblast Growth Factor 1 , Genetics , Pharmacology , Methylnitrosourea , Photoreceptor Cells, Vertebrate , Pathology , Protective Agents , Pharmacology , Proto-Oncogene Proteins c-bcl-2 , Metabolism , Random Allocation , Rats, Sprague-Dawley , Retina , Pathology , Retinitis Pigmentosa , Metabolism , Pathology , bcl-2-Associated X Protein , MetabolismABSTRACT
<p><b>AIM</b>To study the protective effect of ligustrazine against photoreceptor cell injury induced by N-methyl-N-nitrosourea (MNU) in Sprague-Dawley (SD) rats.</p><p><b>METHODS</b>Ligustrazine injections of different doses were injected intraperitoneally into 47-day female SD rats once a day and a single intraperitoneal injection of MNU 60 mg x kg(-1) was given to 50-day rats. At different intervals after MNU treatment,the animals were sacrificed. The apoptotic index of photoreceptor cells was calculated by TUNEL labeling at 24 h following MNU treatment; peripheral retinal damage was evaluated based on retinal thickness at the d 7 after MNU treatment, and the expression of c-jun and c-fos genes was detected by RT-PCR technique.</p><p><b>RESULTS</b>Ligustrazine injection could remarkably increase total thickness of peripheral retina and decrease apoptotic index of photoreceptor cells induced by MNU in a dose-dependent manner. Compared with MNU-treated rats, the gene expression of c-jun and c-fos was time-dependently down-regulated in ligustrazine-treated group.</p><p><b>CONCLUSION</b>Ligustrazine injection partially protects against MNU-induced retinal damage by down-modulating the expression of c-jun and c-fos genes to inhibit apoptosis of photoreceptor cells.</p>
Subject(s)
Animals , Female , Rats , Apoptosis , Dose-Response Relationship, Drug , Genes, fos , Genes, jun , Injections, Intraperitoneal , Ligusticum , Chemistry , Methylnitrosourea , Photoreceptor Cells , Photoreceptor Cells, Vertebrate , Pathology , Plants, Medicinal , Chemistry , Protective Agents , Pharmacology , Pyrazines , Pharmacology , Rats, Sprague-Dawley , Retina , Metabolism , PathologyABSTRACT
<p><b>AIM</b>To investigate the apoptosis induced by diacetyldianhydrogalactitol (DADAG) and its mechanism in human HL-60 leukemia cells.</p><p><b>METHODS</b>Inhibition of proliferation was measured by MTT assay. DADAG-induced apoptosis in HL-60 cells was observed by electron microscopy, flow cytometry and DNA fragmentation assay. The levels of Bcl-2 family proteins were detected by Western blotting. Caspase-3 activity was determined by ApoAlert CPP32 colorimetric assay kit.</p><p><b>RESULTS</b>DADAG exhibited potent antiproliferative activity and induced apoptosis in HL-60 cells. After treatment with DADAG 8 micrograms.mL-1 for various times, the Bcl-XL protein level decreased in a time-dependent manner, while the Bad protein level was upregulated. The caspase-3 activity increased markedly after treatment with DADAG for 24 h. The apoptotic signals were suppressed by z-VAD.fmk (a general inhibitor of caspases), whereas z-DEVD.fmk, a selective inhibitor of caspase-3, only induced partial reversion of the apoptotic effects.</p><p><b>CONCLUSION</b>DADAG-induced apoptosis in HL-60 cells required caspase-3 activation and caspase-3 activation was related with Bcl-2 family members.</p>
Subject(s)
Humans , Antineoplastic Agents , Pharmacology , Apoptosis , Caspase 3 , Caspases , Metabolism , Cell Division , Dianhydrogalactitol , Pharmacology , HL-60 Cells , Proto-Oncogene Proteins c-bcl-2 , Metabolism , bcl-X ProteinABSTRACT
Objective To observe the effect of circadian rhythm on hypnotic median effective dose( ED50) of ketamine. Methods Sixty mice were randomly divided into 4 groups which had 15 mice in each group. They were intraperitoneally injected with ketamine at different times of 2 Am,8 Am,2 Pm and 8 Pm, respectively. Righting reflex was recorded and the value of ED50 was measured with sequential experimental method. Results The hypnotic ED50 of ketamine at 2 Am was(54.57?0.82) mg/kg, with 95% confidence limit of ED50 38.06-78.22 mg/kg;ED50 was(49. 27?0. 12) mg/kg at 8 Am, with 95% confidence limit of ED50 40. 21-60. 37 mg/kg;ED50 at 2 Pm was (42.28?0.21) mg/kg, with 95% confidence limit 37.35 - 47 83 mg/kg;and ED50 at 8 Pm was(57.42?0.14) mg/kg, with 95% confidence limit 37.51-73 72 mg/kg,respectively. The ED50 were significant different at 2 Pm and 8 Pm. However, there were no significant difference in ED50 value among other groups. Conclusion The hypnotic effect of ketamine has circadian rhythm - dependent.