Different Fixatives Give Variable Scenarios in Terms of Epitopes Detection of CD68, CD24, Calretinin, And TME119

Our study aimed to assess five commonly used fixatives-NBF, Davidson, Ethanol, Carnoy, and Bouin-in conserving epitopes of (CD68, CD24, TMEM119, and Calretinin). Twenty-five rats were housed at the College of Veterinary Medicine, University of Baghdad; five rats of each fixative were included with four organs representing our target IHC-specific marker of liver, intestine, brain, and testes. Using a scoring system based on the number of positively stained cells across 25 fields, antigen conservation is highly fixative- and marker-dependent. For CD68, Ethanol and Carnoy displayed the highest staining intensities, suggesting they are superior for maintaining key cellular markers. In contrast, NBF produced a balanced yet unspectacular spread of scores, while Davidson showed moderate effectiveness and Bouin tended to yield mid-range scores. Regarding CD24, most fixatives resulted low-to-moderate staining; however, Bouin distinctly produced a higher number of strongly stained cases, making it particularly effective for this marker. Regarding TMEM119, NBF and Davidson showed moderate, consistent staining, whereas Ethanol struggled, with many sections scoring low. Carnoy excelled by scoring few low-intensity scores and many high-intensity ones. Bouin’s was a good mid-to-high alternative. NBF was least successful at preserving calretinin, with low-intensity staining. After Davidson balanced the distribution, Ethanol and Carnoy showed high intensity, substantially retained immunoreactivity, whereas Bouin’s lagged. Immunohistochemical analysis should match the desired molecular detail or staining consistency. The study found that Bouin's fixative is best for CD24 detection, even if ethanol and Carnoy suit maintain antigens for other markers. NBF and Davidson excel at targeting markers based on study goals.