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The aims of the study are to detect whether there are any possible effects of chronic carbon monoxide (CO) exposure on the argyrophilic nucleolar-organizing region (AgNOR)–associated protein synthesis and evaluate any possible relationship between the amount of AgNOR protein and the level of myocardial injury also and between AgNOR and histopathological evaluation methods. Adult male albino Wistar rats ( n = 18) were randomly divided into three groups (groups A, B, and C). Group A served as control, while groups B and C were rats exposed to CO gas chronically (1000 and 3000 ppm CO concentration with a flow rate of 4 L/min for 30 min/day for 7 days, respectively). Total AgNOR area/nuclear area (TAA/NA) and the mean AgNOR numbers for each myocyte nucleus were determined. There were significant differences among all groups for TAA/NA ratio. These differences were not significant for mean AgNOR numbers. According to the histopathological evaluation scores, there were significant differences between the groups. The differences were significant among the groups for loss of sarcomere pattern. A strong positive correlation between histopathological injury scores and TAA/NA ratio was found ( Rsq = 0.48; p = 0.002), however, the correlation was not significant for mean AgNOR numbers ( Rsq = 0.08; p = 0.25). In conclusion, TAA/NA ratio can be used as an indicator for obtaining information about the level of myocardial damage instead of histopathological evaluation scores.

Introduction: Carbon monoxide (CO) is a colorless, tasteless, odorless, nonirritant gas and CO poisoning affects all organ systems. Aim: We aimed to detect any possible effects of CO exposure on the argyrophilic nucleolar organizing region (AgNOR)-associated protein synthesis of heart cells and whether there is any relationship between AgNOR protein amount and both carboxyhemoglobin (COHb) level and histopathological evaluation methods used for the detection of damage in heart tissue after CO exposure. Materials and Methods: The rats were divided into four groups (control, 1000, 3000, and 5000 ppm), each containing six rats. After CO intoxication, COHb levels were measured and the animals were killed on the 7th day. AgNOR staining was performed in the heart tissue. One hundred nuclei per rat were evaluated, and total AgNOR area/nuclear area and mean AgNOR number were analyzed for each nucleus. The CO exposure groups had significantly higher AgNOR values than the control group ( p < 0.0001). According to cardiomyopathy (CMY) scoring methods, the differences between groups 3 and 4 and groups 1 and 2 were significant ( p < 0.05). A significant positive correlation between AgNOR values and both CMY and COHb levels were detected. Conclusion: The detection of AgNOR protein amount may give information about the CMY levels and be used to detect the CO intoxication levels instead of COHb in later periods.

Yaykasli, Kursat/0000-0001-7550-6370; Saritas, Ayhan/0000-0002-4302-1093; Saritas, Ayhan/0000-0002-4302-1093; Kaya, Ertugrul/0000-0003-0081-682X; Kandis, Hayati/0000-0001-9151-6050 WOS: 000346643700003 PubMed: 24812150 In carbon monoxide (CO) poisoning, CO affects the oxygen-carrying capacity of the hemoglobin molecule. Nucleolar-organizing regions (NORs) are genetic loci on chromosomes that are composed of ribosomal DNA and proteins. NORs can be stained with silver. A total of 18 rats were exposed to CO in three different concentrations (1000, 3000, and 5000 ppm) with 6 rats as controls. The animals were euthanized 7 days after CO intoxication. Lung tissues were taken, embedded in paraffin blocks, and sectioned at 5 m thickness. Argyrophilic nucleolar-organizing region (AgNOR) staining was carried out. One hundred nuclei per individual were evaluated, and total AgNOR number per total nuclear number and total AgNOR area per nuclear area (TAA/NA) for each nucleus were analyzed. The CO exposure groups had significantly higher TAA/NA values and AgNOR numbers than the control group (p < 0.05). Although the differences between 1000 ppm and the other two CO-exposed groups were meaningful (p < 0.05) in the TAA/NA values, there were no differences among the CO exposure groups for the AgNOR number (p > 0.05). The increase in TAA/NA value depends on the increase in the CO exposure. Significant correlations between both the AgNOR values and histopathological scoring methods were found. Therefore, AgNOR staining method may be used as an indirect indicator for evaluating the degree of cell damage rate.