Effects of various fixatives and temperature on the quality of glycogen demonstration in the brain and liver tissues.

The visualization of glycogen deposits in cells and tissues is important for studying glycogen metabolism as well as diagnosis of glycogen storage diseases. Evidence suggests that the demonstration of glycogen can better be enhanced by factors such the choice of fixative and temperature during fixation. Here, we assessed efficacy of neutral buffered formalin (NBF), alcoholic formalin (AF) and paraformaldehyde (PFA) at 4 °C, 37 °C and 40 °C using Periodic Acid Schiff's staining method. Each liver specimen was fixed in NBF and AF while the brain tissues were fixed in NBF, AF and PFA. We found that there was a better PAS staining intensity with the liver tissues fixed in AF compared with NBF. Also, there was no difference in the quality of the staining for tissues fixed in AF at 37 °C, 4 °C and 40 °C, but fixation with NBF at 4 °C gave the best staining quality when compared with 40 °C and 37 °C. Furthermore, hippocampal tissues fixed in AF showed better quality of PAS staining compared with NBF and PFA. A significant increase in staining intensity was observed for PFA when compared with NBF. Superior staining intensity for PAS was observed at 4 °C for hippocampal tissues fixed with NBF, AF and PFA. Taken together our results show that AF at a temperature of 4 °C gave the best result. Hence, glycogen demonstration can better be enhanced by the choice of fixative and temperature during fixation.