Effects of steroid treatment on release of cardiac myosin light chain II in acute myocardial infarction in dogs.
The effect of methylprednisolone sodium succinate (MP) on release of myosin light chain II (LCII) from the myocardium was studied in experimental myocardial infarction (MI). Acute MI was produced in conscious, closed-chest dogs by ligating the left anterior descending coronary artery beyond the first diagonal branch. MP, 30 mg/kg, was administered intravenously just before and 24 hours after MI. After MI, LCII levels in the serum were determined serially up to 240 hours. MI size was determined histologically 10 days after MI. In the MP group, LCII levels in the serum within 72 hours were lower than in the control, and cumulative LCII release for 3 days decreased from 530 +/- 159 to 310 +/- 101 ng/ml (mean +/- standard deviation) (p less than 0.001). However, the peak LCII level appeared later (control vs MP, 63 +/- 27 vs 122 +/- 25 hours, p less than 0.001), and the peak LCII level and cumulative LCII release for 10 days were not decreased by MP treatment. MI size also was not reduced by MP (11.0 +/- 4.4% vs 11.8% +/- 4.5% of the left ventricle, difference not significant). Since the rate of disappearance of LCII is rapid and was not affected by MP, these results suggest that MP treatment early after acute MI delays breakdown of myosin filaments, but cannot prevent it.
D000118:Acetylglucosaminidase / Q000097:blood; D000818:Animals; D003402:Creatine Kinase / Q000097:blood; D004285:Dogs; D008775:Methylprednisolone / Q000031:analogs & derivatives*; D008776:Methylprednisolone Hemisuccinate / Q000378:metabolism* / Q000627:therapeutic use; D009203:Myocardial Infarction / Q000097:blood / Q000201:enzymology* / Q000473:pathology; D009206:Myocardium / Q000201:enzymology / Q000473:pathology; D009218:Myosins / Q000096:biosynthesis* / Q000097:blood
D008776:Methylprednisolone Hemisuccinate; D003402:Creatine Kinase; D000118:Acetylglucosaminidase; D009218:Myosins; D008775:Methylprednisolone