Effects of post-mortem autolysis on the detection of rabies virus genomic RNA and mRNA in mouse brain by using in situ hybridization.

The effects of post-mortem autolysis were studied on the detection of rabies virus RNA in the brains of mice with experimental rabies by using in situ hybridization (ISH). The brains of CVS-infected mice were subjected to autolytic periods in situ of up to 72 h. ISH was performed with 3H-labelled RNA probes for rabies virus glycoprotein gene genomic RNA and mRNA. During the post-mortem period there was progressive loss of signals for genomic RNA and mRNA, which was greater for mRNA. ISH signals in perikarya also changed for genomic RNA from a multifocal to a diffuse distribution during the post-mortem period. Rabies virus antigen was better preserved during the autolytic period. Effects of the agonal state, degradation of RNA by ribonucleases, and diffusion of RNA out of cells prior to fixation could explain the loss of ISH signals in post-mortem tissues.