Browsing by Subject "Drug Administration Schedule"

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Open Access
Naringenin inhibits neointimal hyperplasia following arterial reconstruction with interpositional vein graft
(Lippincott Williams & Wilkins, 2010) Cayci, C.; Wahlquist, T. C.; Seckin, S. I.; Ozcan, V.; Tekinay, A. B.; Martens, T. P.; Oz, M. C.; Ascherman, J. A.
Vessels respond to injury by a healing process that includes the development of neointima. Stenosis secondary to neointima formation is the main cause of failure following arterial reconstructions. Vessel wall homeostasis is regulated by proinflammatory cytokines that affect smooth muscle cell proliferation, growth, migration, and death. We assessed the hypothesis that naringenin, a flavinoid possessing anti-inflammatory, antioxidant, and antiproliferative activities, reduces neointimal hyperplasia (NIH) following vascular injury.Arterial injury was created by interposition grafting of autologous right superficial epigastric vein graft into the right femoral artery (FA) in 48 male Sprague-Dawley rats. Following injury, the rats were divided into 4 groups (n = 12). Two groups were treated with naringenin (100 mg/kg intraperitoneal q daily) for 2 and 4 weeks each while 2 control groups received normal saline for the same durations. For Sham group (n = 10), the FA and vein were isolated without any additional procedure. Rats were killed at the end of treatment regimen in all groups, and FAs were harvested. Thickness of intima was measured in histologic sections, and levels of platelet derived growth factor (PDGF)-BB, TNFα, and Ki67 labeling index (Ki67 LI) were quantified in immunohistochemical analyses to assess the amount of NIH and mechanisms underlying its formation.Although there was no significant difference between the groups at 2 weeks, neointima thickness was lower in the naringenin treated group at 4 weeks (23.7 ± 2.3 vs. 35.6 ± 2.6 μm in control group; P < 0.001). The levels of PDGF-BB, and TNFα were lower in naringenin treated groups at both 2 weeks (PDGF-BB [0.21% ± 0.03% versus 0.39% ± 0.05% in control group, P < 0.001), TNFα (21.2% ± 0.8% vs. 36.1% ± 1.9% in control group, P < 0.001]) and 4 weeks (PDGF-BB [0.25% ± 0.03% vs. 0.57% ± 0.09% in control group, P < 0.001], TNFα [25.5% ± 1.8% vs. 45.0% ± 2.9% in control group, P < 0.001]). Ki67 LI was lower in naringenin treated groups at 2 weeks (13.9% ± 2.8% vs. 18.7% ± 3.7% in control group, P < 0.05), and at 4 weeks (17.5% ± 2.6% vs. 31.1% ± 4.7% in control group, P < 0.001), indicating a lower level of cellular proliferation.Naringenin reduces NIH following arterial reconstruction. This may be mediated by a decrease in PDGF-BB and TNFα levels and the resulting down-regulation of smooth muscle cells' migration and proliferation.
Open Access
Regulation of Homer and group I metabotropic glutamate receptors by nicotine
(Wiley-Blackwell Publishing Ltd., 2005) Kane, J. K.; Hwang, Y.; Konu, O.; Loughlin, S. E.; Leslie, F. M.; Li, M. D.
The present study focuses on the nicotine-induced modulation of mRNA and protein expression of a number of genes involved in glutamatergic synaptic transmission in rat brain over different time periods of exposure. A subchronic (3 days) but not the chronic (7 or 14 days) administration of nicotine resulted in the up-regulation of Homer2a/b mRNA in the amygdala while in the ventral tegmental area (VTA) no change in expression of either Homer2a/b or Homer1b/c was observed. Although the increase in Homer2a/b mRNA was not translated into the protein level in the amygdala, a slight but significant up-regulation of Homer1b/c protein was observed in the same region at day 3. Both Homer forms were up-regulated at the protein level in the VTA at day 3. In the nucleus accumbens, 14 days of nicotine treatment up-regulated mRNA of Homer2b/c by 68.2% (P < 0.05), while the short form Homer1a gene was down-regulated by 65.0% at day 3 (P < 0.05). In regard to other components of the glutamatergic signalling, we identified an acute and intermittent increase in the mRNA and protein levels of mGluR1 and mGluR5 in the amygdala. In the VTA, however, the effects of nicotine on mGluR mRNA expression were long-lasting but rather specific to mGluR1. Nevertheless, mGluR1 protein levels in the VTA area were up-regulated only at day 3, as in the amygdala. These data provide further evidence for the involvement of nicotine in the glutamatergic neuronal synaptic activity in vivo, suggesting a role for the newly identified Homer proteins in this paradigm.