[Animal modeling]-Changes of matrix metalloproteinase 9 and tissue inhibitor 1 in blood and tissues of hypertensive rats

  Objective: To investigate the expression of matrix metalloproteinase 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in serum, brain and vascular tissues of rats with renal vascular hypertension (RHR), blood pressure and both Relationship.

  Method: 80 male SD rats were randomly divided into RHR group (40 rats) and sham operation group (40 rats). In the RHR group, a hypertensive rat model was made by the double-kidney-double-clamp method, and the blood pressure was measured by a rat-tail manometer. Stroke was determined according to the Longa 5 scoring method and pathological results; Western blot and immunohistochemistry were used to determine the expression of MMP-9 and TIMP-1 in brain tissue and blood vessels, and the serum MMP-9 and TIMP-1 levels were detected by double antibody sandwich ELISA.

  Results: Compared with the sham operation group, the blood pressure of rats in the RHR group increased significantly at 2, 4, 6, 8, 10, and 12 weeks after surgery [(157±9.0) vs (128±7.0), (176±10.0) (122±6.0), (194±8.0) ratio (117±6.5), (202±12.0) ratio (124±8.0), (218±15.0) ratio (126.±8.5), (224±20.0) ratio ( 129.±9.0) mmHg, all P<0.05]; 12 weeks after surgery, serum MMP-9 in RHR rats was higher than that in the sham operation group [(783.4±109.79) vs (573.4±109.59) ng/mL, P <0.05] ; While the serum TIMP-1 of RHR rats was lower than that of the sham operation group [(313.02±83.9) vs. (976.19±191.1) pg/mL, P <0.05]. At the same time, the expression of MMP-9 in brain tissue and blood vessel of RHR rats was significantly higher than that of sham operation group (all P <0.05), while the expression of TIMP-1 was significantly lower than that of sham operation group (all P <0.05). Pearson correlation analysis showed that systolic blood pressure was positively correlated with MMP-9 levels in serum, brain and vascular tissues (r=0.557, r=0.774 and r=0.661, both P <0.05), and negatively correlated with TIMP-1 levels Correlation (r=-0.481, r=-0.535 and r=-0.685, all P <0.01).

  Conclusion: The expression of MMP-9 in serum, brain and blood vessel tissues of rats with renovascular hypertension increases, while the expression of TIMP-1 decreases. The trend of the two changes in blood and tissues remains the same. The increase in blood pressure is related to the increase in MMP-9 and the decrease in TIMP-1 in the blood and tissues.