Effects of different fixatives on beta-galactosidase activity.

beta-Galactosidase (beta-Gal) staining is widely used to demonstrate specific gene expression during evaluation of gene targets in vivo. This technique is extremely sensitive to fixation. Optimal fixation conditions are necessary to obtain the maximal beta-Gal activity. In this experiment, Carnoy's and three different aldehyde fixatives were used at different temperatures and over different time points. Kidneys from LacZ-stop-human alkaline phosphatase (ZA/P) double reporter mice were used to generate positive material for the experiment. The results show that glutaraldehyde combinative solution (LacZ) produced the most consistent and reliable results. Paraformaldehyde and formaldehyde were effective as fixatives only at 4C for a period of less than 4 hr, and Carnoy's solution destroyed beta-Gal activity.