Objectives:

The purpose of the study is to investigate whether there is any relationship between mean argyrophilic nucleolar organizing regions (AgNOR) number and total AgNOR area/total nuclear area (TAA/TNA) ratio and the levels of brain hypoxia after exposure to different acute doses of carbon monoxide (CO) gas.

Methods:

Each experimental group was exposed to CO gas (concentrations of 1,000, 3,000 and 5,000 ppm). Then, the rats were anesthetized, and blood samples were taken from the right jugular vein for carboxyhemoglobin levels detection. The rats were sacrificed on seventh day. AgNOR staining was applied to brain tissues. TAA/TNA and mean AgNOR number were detected for each nucleus.

Results:

Significant differences were detected among the all groups for TAA/TNA ratio, mean AgNOR number and carboxyhemoglobin level. According to double comparison of groups, the differences between control and 1000ppm, control and 3000ppm, control and 5000ppm and 1000 and 5000ppm were significant for TAA/TNA ratio. When mean AgNOR number to be considered, significant differences were detected between control and 1000ppm, control and 3000ppm, control and 5000ppm and 1000 and 3000ppm.

Conclusion:

AgNOR proteins may be used for early detection of the duration, intensity and damage of brain injury caused by CO intoxication. Thus, effective treatment strategies for the prevention of hypoxic conditions may be developed.