Biomarkers of oxidative stress and protein–protein interaction in chronic obstructive pulmonary disease

<p><b>Content:</b> The increased oxidative stress in chronic obstructive pulmonary disease (COPD) patients is the result of increased inhaled oxidants, generated by various cells of the airways.</p> <p><b>Objective:</b> The investigation included measurements of malondiadehyde (MDA), uric acid, ascorbic acid, and matrix metalloproteinase-12 (MMP-12) in COPD patient. We also performed genetic analysis for protein–protein interaction (PPI) network.</p> <p><b>Materials and methods:</b> The study was conducted on healthy subjects with normal lung function (NS, 14 subjects) and 28 patients (Global Initiative for Chronic Obstructive Lung Disease (Gold) 1 and Gold 2) with COPD.</p> <p><b>Results:</b> There was significant (<i>p</i> < .001) increase in MMP-12, MDA and uric acid levels as compared to healthy controls. A significant (<i>p</i> < .001) decline in ascorbic acid level was observed in COPD patients. The PPI was found to be 0.833 which indicated that proteins present in COPD are linked.</p> <p><b>Discussion and conclusion:</b> This study suggests oxidative stress plays an important role in COPD and the PPI provide indication that proteins present in COPD are linked.</p

The cytotoxicity of Ag NPs of different sizes.

<p>The cytotoxicity of 120-nm and 20-nm Ag NPs against HeLa, OEC-M1, Beas2B, and Hs68 cells was evaluated by trypan blue staining (*indicates <i>P<</i>0.05).</p

Morphological analysis of <i>N. gonorrhoeae</i> in response to 120-nm Ag NPs.

<p><i>N. gonorrhoeae</i> cells (1×10⁷ cfu/ml) were treated with or without Ag NPs (5 µg/ml) for 1 h, and the morphology of <i>N. gonorrhoeae</i> was analyzed by (A) SEM (20,000×) and (B) TEM (13,500×). (C) <i>N. gonorrhoeae</i> cells (1×10⁷ cfu/ml) were treated with Ag NPs (10 µg/ml) for 1 h, and observations using TEM (13,500×) showed that the Ag NPs entered and accumulated in the cells. (D) The depth of the <i>N. gonorrhoeae</i> cell wall was measured by TEM (1,100×), and the cell viability was expressed as the percentage of intact bacteria in comparison to the Ag NPs-free PF-68 control. The data are expressed as the mean±SD for three separate experiments (* indicates <i>P</i><0.001).</p

Concentration of Ag⁺ ions leaching from Ag particles.

<p>The leaching Ag ions from different sizes of Ag particles at MIC concentration were detected by Inductively Coupled Plasma-Mass Spectrometer (ICP-MS).</p

The anti-bacterial activity of Ag particles against <i>N. gonorrhoeae</i>.

<p>(A) The size and structure of cell-free Ag particle samples with dispersant were analyzed by TEM (3,500-60,000×). (B) <i>N. gonorrhoeae</i> cells (4×10³ cfu/ml) were incubated with Ag particles (20 nm, 120 nm, and 1 µm) at doses of 5, 10, 20, and 25 µg/ml for 30 min, followed by inoculation by spreading onto GC agar plates for 24 h at 37°C. The number of colonies was calculated, and the data are expressed as the mean±SD for three separate experiments (% of Ag NPs-free PF-68 control, * indicates <i>P</i><0.05 compared to its' own control; ^# indicates <i>P</i><0.05 compared to 1 µm Ag particles).</p

Ag NPs form a complex with cefmetazole (CMZ).

<p>(A) Cefmetazole solutions (1 to 25 mg/ml) were incubated with or without Ag NPs (10 mg/ml) for 24 hours. After centrifugation, the supernatant was analyzed at an O.D. of 300 nm using a spectrophotometer. (B) A cefmetazole solution (1 mg/ml) was incubated with or without Ag NPs (5 or 25 µg/ml) for 24 hours. After centrifugation, the supernatant was analyzed at an O.D. of 300 nm using a spectrophotometer (* indicates <i>P</i><0.001).</p

Minimum inhibitory concentration (MIC) values of silver nanoparticles of different sizes against a standard <i>N. gonorrhoeae</i> strain.

<p>Minimum inhibitory concentration (MIC) values of silver nanoparticles of different sizes against a standard <i>N. gonorrhoeae</i> strain.</p