| ObjectsThe generation, progress of atherosclerosis and the formation and rupture of instability plaque are associated with Matrix Metalloproteinase ( MMPs) and Matrix Metalloproteinase Tissue Inhibitor (TIMPs). MMP - 2 and TIMP - 2 excreted by mononuclear/phagocyte and endothelial cells are one of the most important factors. Mononuclear cells might induce MMP -2 excretion of other cells a-round them through interaction of cells 'suface. Endothelial cells in the plaque overexpress MMP - 2 are coherent with the infiltration of monocytes. There might be some relationship between endothelial cells and monocytes. Statins could stabilize plaque and prevent rupture of unstable plaque. However, there has been no report if statins might regulate MMPs and TIMPs expression and excretion. In my experiment I want to investigate MMP - 2 and TIMP - 2 expression by interaction between vascular endothelial cells and monocytes, and the regulated effects of Pravastatin.MethodsAt first, HUVECs were cultured in 24 - well plates by modified Jaffe method and THP - 1 were cultured, also. In the interaction experiment, a co -cultured system of monocyte and endothelial cell was established through added THP -1 to HUVECs in various ratio as the HUVECs cultured in vitro were sub - confluent. 5 groups are divided: HUVECs cultured only, THP - 1 cultured only, co - cultured of HUVEC and THP - 1 in the ratio 1:2, 1:1 or2:1. In thePravastatin operation experiment, select 1:1 co - cultured system and 4 groups are divided; control group ( no Pravastatin added) , experiment group (the concentration of Pravastatin is divided into 0. 1 umol/ml, 0. 5umol/ml, 1. 0umol/ ml respectively ). Activity and expression of MMP - 2 and TIMP - 2 in co - culture system were studied by zymography and reverse zymography.Results24 hours after co - culture, compared with HUVEC cultured only, the activity of proMMP - 2 of co - cultured system in the ratio 1:2, 1:1 or 2: lincreased by 2. 09 - , 2. 46 - , 2. 07 - folds respectively (n = 8, P <0. 01). And only co - cultured system could excrete active MMP -2. Reverse zymography revealed that, in the co - cultured system, the excretion of TIMP - 2 decreased (P <0. 05) , but no mixed ratio involved. The activity of proMMP -2 and MMP -2 after administrating Provastatin decreased greatly. Compared with controlled group, the excretion of proMMP - 2 of different concentration Prafastatin was 96. 71% , 78. 13% and 50. 42% respectively ( n = 8, P < 0. 05) . 1. 0|xmol/ml Provastatin restrained active MMP -2 completely. However, Provastatin had no obvious influence to TIMP - 2 in this experiment.DiscussionThe adhesiveness between vascular endothelial cells and monocytes was very important to the formation and development of atherosclerotic plaque and the formation and rupture of unstable plaque. Some researches thought that MMPs and/or TTMPs expressed and excreted by monocytes and vascular endothelial cells participated in the above - mentioned pathologic process. This experiment studied the interaction between vascular endothelial cells and monocytes affected on MMP - 2 and TIMP - 2 activities; at the same time, using Pravastatin to detect its effect on MMP - 2 and TIMP - 2 activities. Results showed that interaction between vascular endothelial cells and monocytes might contribute to the excretion and activation of proMMP - 2 and MMP - 2, only co-cultured system could produce active MMP -2. The excretion and activation of proMMP - 2 and MMP - 2 were associated with the ratio of vascular endotheli-al cells and monocytes, co - cultured in ratio 1:1 was more better than in ratio 1: 2 and 2: 1. This might because cell surface adhesive molecules or other cell surface molecules in monocytes and vascular endothelial cells existed in different binding states, which led to different active degree of signal pathway, then made the synthesis, excretion and activation of enzymes different. Experiment also found that interaction between vascular endothelial cells and monocytes might restrain activation of TIMP...
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