| Background and objectiveInguinal hernia is a common disease. According to statistics, the incidence of inguinal hernia is 3～5%o,but about the male people that over 60 years old,the incidence will up to 1～5%.But so far, the basic mechanism of the formation of inguinal hernia is not clear. Generally, the inguinal hernia is caused by many factors, such as the anatomy and the dynamic factors, that is the weakness of the posterior wall of inguinal canal and the increase of the intra-abdominal pressure.Recently, some scholars put forward to the factor of the biochemical of tissue. In the extracellular matrix (ECM), The decrease of typeⅠand the relatively increased of typeⅢ, resulting inⅠ/Ⅲcollagen imbalance, so that the connective tissue metabolism, resulting in the aponeurosis and fascia in inguinal area is weak and missing and eventually the occurrence of inguinal hernia, that indicating that the relation of the collagen metabolism and the occurrence of inguinal hernia is closely.Collagen is the major components of the extracellular matrix (ECM). Its metabolism is adjusted by the matrix metalloproteinase (MMPs) and the tissue inhibitors of metalloproteinase (TIMPs). MMPs is Zn2+dependent endopeptidase enzymes that can affect the cross-linking and maturation ofⅢcollagen, has important role in ECM degradation. And the TIMPs as a specificity natural inhibitor of MMPs, can combine with the activation of MMPs as 1:1, preventing its binding with substrate, thus indirectly involved in collagen metabolism. MMP-2 has playing a major role in the metabolism ofⅠandⅢcollagen,and TIMP-2 is specific inhibitor of MMP-2, playing mainly by blocking the activation of MMP-2 zymogene and the binding of activated MMP-2 with substrate.When we review the literature, we found that the studies about the relationship that the expression of MMPs and TIMPs in the connective tissue and the occurrence of inguinal hernia, were very little. Currently, the relationship of the expression of MMPs and TIMPs in the obliquus externus abdominis aponeurosis and the primary inguinal hernia had not been reported in the international and domestic. In this study, we use the reverse transcript polymerase chain reaction (RT-PCR) technology to analyse the relationship of the expression between MMP-2(mRNA) and TIMP-2 (mRNA) in the obliquus externus abdominis aponeurosis of adult patients with inguinal hernia with inguinal hernia, in order to improve the pathogenesis of inguinal hernia from the biochemical of tissue, provide the basis to the prevention and clinical therapy of inguinal hernia.Materials and methods1. Material:Cut the obliquus externus abdominis aponeurosis of the anterior wall of the inguinal canal in 25 patients with inguinal hernia (indirect inguinal hernia in 15 cases, direct inguinal hernia in 10 case) as the experimental group; Then take the obliquus externus abdominis aponeurosis in 10 patients that had non-hernia in the same time as the control group. And then put them in cold refrigerator on -80 degree.2.Reagent sources:TRNzol Reagent kit, TIANScript cDNA first strand synthesis kit, 2×Taq PCR MasterMix kit were purchased from Tian root Biochemical Technology Company of Beijing; The specific primers were purchased from the Biological Engineering Company of Shanghai.3. RT-PCR:We handled the specimens with the technology of two-step RT-PCR, and carried out the experimental procedures according to the kit instructions.4.Statistrical analysis:All results were recorded as (x±s), The SPSS16.0 statistical software was used for statistical analysis. The single factor analysis of variance was used to compare during many groups, and the t test was used to compare between two samples. The correlation of the date was analyzed by Pearson method. The P value that less than 0.05 was considered statistically significant.Results1. The expression of MMP-2(mRNA) and TIMP-2(mRNA) in the indirect inguinal hernia group. direct inguinal hernia group and control group.The expression of MMP-2 in indirect inguinal hernia group was 0.87±0.20, in the direct inguinal hernia group was 1.11±0.17, in the control group was 0.83±0.23. The direct inguinal hernia expressed significantly higher, compared with the control group (p=0.008<0.05) was statistically significant. Compared the indirect inguinal hernia group and the control group (p=0.0616>0.05),it has no statistically significant.The expression of TIMP-2 in indirect inguinal hernia group was 0.92±0.19, in the direct inguinal hernia group was 0.61±0.16, in the control group was 1.06±0.21. The direct inguinal hernia expressed significantly higher, compared with the control group (p=0.000<0.05) was statistically significant. Compared the indirect inguinal hernia group and the control group (p=0.07>0.05),it has no statistically significant. 2. The relationship of the expression of MMP-2(mRNA) and TIMP-2(mRNA) and age.The expression of MMP-2 was increased with age, and was positively correlated with age (r=0.365, p=0.026)The expression of TIMP-2 was decreased with age, and was negatively correlated with age (r=-0.359, p=0.034)3. The expression of MMP-2(mRNA) and TIMP-2(mRNA) and its relationship with smoking.The expression of MMP-2 in non-smoking group(16cases) was 0.89±0.198,in smoking group(19cases) wasl.008±0.123. Compared the smoking group with the non-smoking group, the smoking group's expression was high (t=6.782 p=0.013< 0.05),the difference was statistically significant.The expression of MMP-2 in non-smoking group was 0.983±0.207,in smoking group was 0.800±0.207. Compared the smoking group with the non-smoking group, the smoking group's expression was high (t=5.557 p=0.024<0.05), the difference was statistically significant.Couclusion1. In the obliquus externus abdominis aponeurosis, the MMP-2 is high expression and TIMP-2 low expression. So we can say they have participated in the degradation of collagen of ECM and played an important role in the process of the direct inguinal hernia. But they don't work in the formation of the in-direct inguinal hernia.2. Increase with age, the expression of MMP-2 is increase and the expression of TIMP-2 is decrease, and promote the degradation of the metabolism in ECM, thus increase the incidence of inguinal hernia.3. Smoking may promote the high expression of MMP-2 and the low expression of TIMP-2 in the connective tissue of body, induced the collagen metabolism in ECM, speeded up the process of the inguinal hernia. |
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