Differential expression of extracellular matrix remodeling genes in rat model of hemorrhagic shock and resuscitation

Matrix metalloproteinases (MMPs) and their specific physiological inhibitors, tissue inhibitors of metalloproteinases (TIMPs), are thought to play an essential role in tissue repair, cell death and morphogenesis. We have previously discovered unexpected up-regulation of genes coding for multiple MMP/TIMP family members in a rat model of hemorrhagic shock and resuscitation. However, the effect of different resuscitation protocols at the level of protein expression and function remains unknown. Male Sprague-Dawley rats (n = 50; 10/group) were subjected to a three-stage volume controlled hemorrhage and resuscitated as follows: 1) lactated Ringer's solution (LR), 3:1 volume of lost blood; 2) 7.5% hypertonic saline (HTS), 9.7 ml/kg; 3) plasma, 1:1 volume. Sham hemorrhage and sham resuscitation groups were used as controls. Expression of lung and spleen MMPs (-2, -7, -9, -10, -14, and -16), and TIMPs (-1, -2, and -3) was analyzed at transcriptional, functional and protein expression level using RT-PCR, ELISA, Western blotting, and gelatin zymography techniques. Spleen was affected more than lung by the resuscitation strategy and the largest number of changes was caused by HTS resuscitation. RT-PCR confirmed an increased levels of MMP-2, MMP-9, MMP-7, MMP-14, MMP-16, and TIMP-1, TIMP-2 in the spleen of HTS group compared to sham groups, whereas in lungs transcriptional levels of only TIMP-3 and TIMP-1 were significantly changed. Expression of MMP and TIMP in lung and spleen following hemorrhage is modulated by the resuscitation strategy.