Ng E K, Barent B L, Smith G S, Joehl R J, Murayama K M
Department of Surgery, Lakeside DVA Medical Center, Chicago, Illinois, USA.
J Surg Res. 2001 Mar;96(1):6-9. doi: 10.1006/jsre.2000.6048.
Severe hyperstimulation and duct obstruction pancreatitis (SHOP) is characterized by pancreatic fibrosis and loss of acinar cell mass. MMP-2 and MMP-9 are type IV collagenases and gelatinases. We hypothesized that fibrosis results from disruption of the normal collagen homeostasis and that altered activity of the type IV collagenases may contribute to pancreatic fibrosis in SHOP.
SHOP rats (n = 15) were prepared with pancreatic duct obstruction and cerulein (50 microg/kg/d, ip) hyperstimulation. Pancreas from unoperated control (n = 8), 48 h SHOP (n = 8), and 96 h SHOP (n = 7) rats was harvested, homogenized, and assayed for protein concentration (BCA method). Type IV collagenase (MMP-2 and MMP-9) expression was measured by zymography using gelatin as substrate. Type IV collagenase activity was quantified with a fluorescence assay.
Expression of the active form of MMP-9 decreased while latent MMP-9 and active and latent MMP-2 increased on gelatin zymography. Activity of type IV collagenases (MMP-2 and MMP-9) progressively decreases with SHOP injury. The differences between expression and activity are likely due to posttranslational regulators such as MT-MMPs and TIMPs.
Collagenase expression and activity are decreased in the SHOP model of pancreatitis, suggesting a decrease in the homeostatic mechanisms for type IV collagen in the extracellular matrix. Therefore, early fibrosis in the SHOP model is, at least in part, due to alterations in collagen homeostasis and not simply increased collagen production.
严重过度刺激和导管阻塞性胰腺炎（SHOP）的特征是胰腺纤维化和腺泡细胞团丢失。基质金属蛋白酶-2（MMP-2）和基质金属蛋白酶-9（MMP-9）是IV型胶原酶和明胶酶。我们推测纤维化是由正常胶原稳态破坏引起的，并且IV型胶原酶活性改变可能导致SHOP中的胰腺纤维化。
通过胰腺导管阻塞和蛙皮素（50微克/千克/天，腹腔注射）过度刺激制备SHOP大鼠（n = 15）。收集未手术对照（n = 8）、48小时SHOP（n = 8）和96小时SHOP（n = 7）大鼠的胰腺，匀浆并测定蛋白质浓度（BCA法）。以明胶为底物，通过酶谱法测量IV型胶原酶（MMP-2和MMP-9）的表达。用荧光测定法定量IV型胶原酶活性。
在明胶酶谱上，MMP-9活性形式的表达降低，而潜伏性MMP-九、活性和潜伏性MMP-2增加。IV型胶原酶（MMP-2和MMP-9）的活性随着SHOP损伤而逐渐降低。表达和活性之间的差异可能归因于翻译后调节因子，如膜型基质金属蛋白酶（MT-MMPs）和基质金属蛋白酶组织抑制因子（TIMPs）。
在胰腺炎的SHOP模型中，胶原酶的表达和活性降低，提示细胞外基质中IV型胶原的稳态机制降低。因此，SHOP模型中的早期纤维化至少部分是由于胶原稳态的改变，而不仅仅是胶原产生增加。
