[Expression of MMP-2, MMP-9 and TIMP-1 and the effects of methylprednisolone in EAM].
OBJECTIVE
To study the function of MMP-2 (matrix metalloproteinase-2), MMP-9 (matrix metalloproteinase-9) and TIMP-1 (tissue inhibitor of metalloproteinase-1) in the pathogenesis of EAM (experimented autoimmune myositis) rats, and to evaluate the effect of methylprednisolone on the mRNA and protein expression of MMP-2, MMP-9 and TIMP-1.


METHODS
The expression levels of MMP-2, MMP-9 and TIMP-1 in the peripheral blood, spleen lymphocytes and muscles were examined among the EAM group, EAMM group and control group by RT-PCR and immunohistochemical techniques.


RESULTS
1. The degree of episode in the EAMM group was lower than that in the EAM group. Also, the infiltration of the inflammatory cells and the necrosis of the muscles were milder in the EAMM group than those in the EAM group. 2. The mRNA expression of MMP-2 and MMP-9 in the lymphocytes of the peripheral blood and spleen and the protein expression of MMP-2 and MMP-9 in the muscle tissues all increased significantly in the EAM group compared with those of the control group. However, the mRNA and protein expression of MMP-2 and MM-9 was suppressed significantly in contrast with that in the EAM group. 3. The mRNA and protein expression of TIMP-1 in the EAMM group increased with statistical significance compared with that in the EAM group.


CONCLUSIONS
The upregulation of the expression of MMP-2 and MMP-9 may be related with the onset of EAM. TIMP-1 may be involved in the suppression of immunoreaction. Methylprednisolone may reduce the pathological damages of EAM, and this protective mechanism may be due to the inhibited expression of MMP-2 and MMP-9 and promoted expression of TIMP-1.
Zhang
Ning
N
Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, China.
Xiao
Bo
B
Li
Jing
J
D000818:Animals; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis* / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis* / Q000235:genetics; D008775:Methylprednisolone / Q000494:pharmacology*; D018482:Muscle, Skeletal / Q000473:pathology; D020721:Nervous System Autoimmune Disease, Experimental / Q000201:enzymology* / Q000276:immunology / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis* / Q000235:genetics
D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D008775:Methylprednisolone