The viral genome in experimental murine Coxsackievirus B3 myocarditis: a Northern blotting analysis.

The presence of viral genomes in the murine heart in experimental coxsackievirus B3 myocarditis was investigated by Northern blotting analysis. Four-week-old C3H/He mice were inoculated with coxsackievirus B3. After sacrifice, the hearts were divided into 3 parts. Total RNA was extracted from one part of the heart. The other two parts were used for investigation of histopathology and of virus titer by plaque assay. The 32P-labeled cDNA probe was derived from the 5' end sequence of the coxsackievirus B3 genome. Northern blot autoradiograms of heart RNA were positive for viral RNA until day 7 and negative after day 10 and in control (uninfected) hearts. Positive autoradiograms always had the strongest signal at about 7.4 kilobase, corresponding to the size of the complete genome of the virus. The viral genomes were detected earlier than the appearance of the histopathologic changes in the murine heart. This type analysis of the viral genome in the murine myocardium may be useful in evaluating the effects of specific drugs on experimental viral myocarditis at the level of the viral genome.