Role of matrix metalloproteinases-9,collagen Ⅲ and fibronectin in premature rupture of fetal membranes

Objective: To observe the expression levels of matrix metalloproteinases-9(MMP-9),type Ⅲ collagen and fibronectin(FN) in the serum and fetal membranes in women with premature rupture of membrane,and investigate their roles in premature rupture of membranes.Methods: Twenty women with preterm premature rupture of membranes,20 women with term fetal rupture of membranes and 20 women with normal full-term pregnancy were divided into the pPROM group,tPROM group and control group,respectively.The levels of MMP-9,type Ⅲ collagen and FN in the serum and fetal membranes in three groups were detected using the enzyme-linked immunosorbent assay and immunohistochemistry,and the results of those were analyzed.Results: The differences of the serum levels of MMP-9,type Ⅲ collagen and FN between three groups were statistically significant(P<0.01),the serum level of MMP-9 in tPROM group was significantly higher than that in pPROM group,and the serum level of MMP-9 in pPROM group was significantly higher than that in control group(P<0.01).The positive rates of MMP-9 in fetal membranes of pPROM group and tPROM group were significantly higher than that in control group(P<0.01),the positive rate of MMP-9 in tPROM group was significantly higher than that in pPROM group,and the difference of which between two groups was not statistically significant(P>0.05).The positive rates of type Ⅲ collagen and FN in fetal membranes of pPROM group and tPROM group were lower than that in control group(P<0.01),the positive rates of type Ⅲ collagen and FN in tPROM group was lower than that in pPROM group,and the difference of which between two group was not statistically significant(P>0.05).Among pPROM group and tPROM group,the level of MMP-9 was negatively related to the type Ⅲ collagen level(r=-0.874,r=-0.988,P<0.01),the level of MMP-9 was positively related to the FN level(r=-0.760,r=-0.875,P<0.01),and the level of type Ⅲ collagen was positively related to the FN level(r=0.529,r=0.876,P<0.05).In the fetal membrane tissue,the expression level of MMP-9 was negatively related to the level of type Ⅲ collagen(r=-0.468,P<0.01),the expression level of MMP-9 was negatively related to the level of type Ⅲ collagen(r=-0.493,P<0.01),and the level of type Ⅲ collagen was positively related to the level of FN(r=0.885,P<0.01).Conclusions: MMP-9,type Ⅲ collagen and FN are involved in the development of premature rupture of membranes.The levels of MMP-9 in serum and fetal membranes increasing and type Ⅲ collagen level decreasing can lead to the occurrence of premature rupture of fetal membranes.