Subacute carbon monoxide exposure alters AgNOR number and area ratio in the cerebral cortex of rats

We aimed to evaluate the effects of hypoxia induced by different levels of subacute carbon monoxide (CO) exposure on the total AgNOR area/total nuclear area (TAA/TNA) ratio and mean AgNOR number in rat cerebral cortical tissue. Eighteen Albino Wistar adult male rats were randomly divided into three groups (control as group A, 1000ppm and 3000ppm concentration of CO gas exposed as group B and C, respectively). CO gas was chronically given as 30 min a day during seven days.

Statistically significant differences were found among the groups for both mean AgNOR number (χ2 = 12.051, p = 0.002) and TAA/TNA (χ2 = 12.316, p = 0.002), respectively. When the two groups are compared in terms of TAA/TNA ratio, statistically significant differences were detected between control and 1000ppm (Z = -2.882, p = 0.004), between control and 3000 ppm (Z = -2.882, p = 0.004) for TAA/TNA ratio. Statistically significant differences were found between control and 1000 ppm (Z = -2.882, p = 0.004), between control and 3000 ppm (Z = - 2.887, p = 0.004) for mean AgNOR number.

It is important to determine new markers with high sensitivity and easy to apply in order to determine the effect of toxication in different organs and tissues (especially brain tissues) that are subacutely exposed to carbon monoxide intoxication. It seems that AgNOR may be used for this purpose. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Department of Emergency Medicine, Sivas Numune Education and Research Hospital, Sivas, Turkey Department of Biology, Faculty of Fen, Cumhuriyet University, Sivas, Turkey Department of Emergency Medicine, Faculty of Medicine, Aksaray University, Aksaray, Turkey Emergency Department, Antalya Training and Research Hospital, Health Science University of Turkey, Antalya, Turkey Anesthesia Department, Antalya Training and Research Hospital, Antalya, Turkey The authors declare no competing interests. The study was conducted after obtaining ethical approval from the Sivas Numune Education and Research Hospital Animal Experiments Local Ethics Committee (Date: 17 June 2025; Approval No. 54). The authors confirm that this manuscript is original, has not been published previously, and is not under consideration for publication elsewhere.

All authors have reviewed and approved the final version of the manuscript. Ethical approval for animal experiments was obtained from the appropriate institutional ethics committee. We have not used any AI tools or technologies to prepare this manuscript.

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