Expression of matrix metalloproteinase-2, -9 and their inhibitor-1 in hypertrophic scars / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the gene expression of matrix metalloproteinases (MMP-2, MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) in proliferative and mature hypertrophic scars.</p><p><b>METHODS</b>Total RNA from 8 normal skin samples and from 16 human hypertrophic scar samples of different maturing stage was respectively extracted, and then mRNA was isolated. The gene expressions of MMP-2, MMP-9 and TIMP-1 in these samples were examined with reverse transcription-polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The gray scale ratio of MMP-2, MMP-9 and TIMP-1 transcription in normal skin were (3.8 +/- 0.7)%, (5.8 +/-4.4)%, (30.3 +/- 3.0)%, respectively, which were obviously higher than those in proliferative hypertrophic scar [(14 +/- 5)%, (18 +/- 5)%, (38 +/- 4)%, P < 0.05]. The expression of MMP-2 and MMP-9 genes in mature hypotrophic scar returned to normal level, but that of TIMP-1 remained high when compared with that of normal level (P < 0. 05).</p><p><b>CONCLUSION</b>The increase in MMP-2, MMP-9 and TIMP-1 gene expression might be involved in the formation of hypertrophic scars, while the lowering of MMP-2 and MMP-9 gene expression might be associated with the maturation of hypertrophic scars.</p>

The effect of hyperoxic Ringer's solution on the rabbits with inhalation injury at early postburn stage / 中华烧伤杂志

<p><b>OBJECTIVE</b>To investigate the effect of hyperoxic Ringer's solution on inhalation injury given at early postburn stage in rabbit.</p><p><b>METHODS</b>Seventy-seven rabbits were randomly divided into four groups, i.e. A (normal control, n = 5, without injury), B (n = 24, with Ringer's solution infusion for 10 days after injury), C (n = 24, with hyperoxic Ringer's solution infusion for 10 days after injury) and D (n = 24, without treatment after injury) groups. The rabbits in B, C and D groups were observed on 1 post injury day (PID), 2 PID, 3 PID, 5 PID, 7 PID and 10 PID, with 4 in each time points. The vital signs and survival rate were observed and the blood gas analysis, the WBC and PMN in the peripheral blood, ratio of wet/dry weight (W/D) of the lung tissue, the MDA, SOD contents in the pulmonary tissue, and the pulmonary pathomorphology were determined by corresponding methods.</p><p><b>RESULTS</b>The respiratory rate of the rabbits increased postburn, which was accompanied with gasping breath, flapping of nasal alae, frequent cough, and increased buccal and nasal secretion. Dry and wet rales were heard in the lungs after injury. The survival rate in D, B and C groups was 13.3%, 27.8% and 65.6%, respectively. Metabolic acidosis was identified in these groups by blood gas analysis. The indices of PaCO2, WBC, PMN, W/D, MDA in B, C and D groups were higher than those in A group in the order of D > B > C > A groups. While the pH, PaO2 value and SOD content in D group were lower than those in A group in the order of D < B < C < A groups (P < 0.05). Pathomorphological examination revealed that pulmonary volume increased after the injury with microscopic inflammatory changes in pulmonary tissue in B, C and D groups. While the extent and degree of injury in C group after the treatment of hyperoxic Ringer's solution were evidently less severe than those in other groups.</p><p><b>CONCLUSION</b>Early administration of hyperoxic Ringer's solution during the early postburn stage could be beneficial to the management of inhalation injury.</p>