Effect of indomethacin in the late phase of coxsackievirus myocarditis in a murine model.

Previous studies have shown that indomethacin administered during the early phase of experimental myocarditis may exacerbate the disease process. It is unknown whether late administration of this agent is safe. Therefore, the effect of indomethacin administration during the late phase of coxsackievirus B3 murine myocarditis was investigated. Forty 3-week-old CD1 mice each received a 3 x 10(4) median tissue culture-infective dose of coxsackievirus intraperitoneally. On day 10 of infection, mice were randomized to receive either indomethacin or normal saline solution for 10 days, and 10 mice from each group were killed on days 20 and 30 of infection. Heart weight and size and serum atrial natriuretic peptide were similar in both groups on days 20 and 30. On day 20, pathologic scores for the degree of inflammation and necrosis were 1.7 and 1.0 for the indomethacin group versus 1.4 and 1.7 for the saline solution group. On day 30, pathologic scores were 0.3 and 0.6 for the indomethacin group versus 0.5 and 0.6 for the saline solution group. In addition, mineralization was absent in indomethacin-treated animals on day 20 after infection, but it was present in half of the control animals at that time. The degree of mineralization did not differ on day 30 between the two groups. These findings suggest that indomethacin given in the late phase of coxsackievirus myocarditis has no deleterious effects at 30 days.