Extracellular matrix gene expression in the left ventricular tissue of spontaneously hypertensive rats

The aim of this study was to investigate the extracellular matrix gene expr ession in the hypertrophied left ventricular tissue of spontaneously hypert ensive rats (SHR) and Wistar-Kyoto (WKY) rats, at early and mature ages. In terestingly, with age, a marked increase (+85% and +187% at 25 and 30 weeks of age, respectively, p < 0.01, vs 5 weeks) in matrix metalloproteinase-1 (MMP-1) mRNA levels in SHR and a progressive decrease (-50%, -70%, -78%, -7 0% at 10, 15, 25 and 30 weeks, respectively, p < 0.01, vs 5 weeks) in WKY w ere seen. Moreover, mRNA levels were significantly lower in SHR at 5 weeks. The analysis of mRNA expression for the tissue inhibitor of metalloprotein ase-1 (TLMP-1) showed a significant increase in WKY (+44% and +44%, vs 15 a nd 25 weeks, respectively, p < 0.05), whereas there were no significant cha nges in SHR with development. At 30 weeks TIMP-1 mRNA levels were significa ntly reduced in SHR. Temporal trends of procollagen alpha 1(I) and procolla gen alpha 1(III) mRNA levels were similar in both strains, but lower levels for procollagen alpha 1(III) were found in SHR at 5 and 30 weeks. Although no significant differences were measured between the strains, mRNA levels for fibronectin were found decreased in WKY and increased in SHR with age. The results of the present study suggest an altered balance between collage n deposition and collagen degradation with development in this model of lef t ventricular hypertrophy and hypertension.