| ObjectiveTo establish a new model of pancreatic fibrosis in rats by ethanol and lipopolysaccharides(LPS, endotoxin). And to observe the effect of curcumin on pancreatic fibrosis in rats by feeding them with curcumin and make a preliminary study on the mechanism.Methods1. In order to establish a rat model of chronic pancreatitis, twenty-four one-month old male SD rats were randomly divided into 4 groups: control group, alcohol group, lipopolysaccharides (LPS) group and model group. All the rats were fed with the same food. Rats in control group and LPS group were fed with water, and the others were fed with 25% alcohol. After twelve weeks, the rats in model group and LPS group were intraperitoneal injected with LPS (2mg/Kg),once a week, for 4 times. All rats were killed 1 week after the last injection. Pancreatic morphology was conducted with haematoxylin-eosin stain, collagen deposition was determinated by Masson stain and the content of amylase and lipase in pancreatic tissue homogenate were evaluated by colorimetry.2. To study the effect of pancreatic stellate cells in this model,α-smooth muscle actin (α-SMA) and collagen I were observed by immunohistochemistry. The expression ofα-SMA mRNA and fibronectin mRNA in the pancreas were determinated by RT-PCR. And the expression of proteinα-SMA was determinated by Western blot.3. To observe the effect of curcumin in rats pancreatic fibrosis, eighteen one-month old male SD rats were randomly divided into control group, model group and treatment group. After fed by 25% alcohol for twelve weeks, the rats in model group and treatment group were injected with LPS once a week, in the following 4 weeks. The rats in the treatment group were also fed with curcumin mixed with 25% alcohol. All the rats were killed after 17 weeks. Pancreatic morphology was conducted with haematoxylin-eosin stain, collagen deposition was determinated by Masson stain and the content of amylase and lipase in pancreatic tissue homogenate were evaluated by colorimetry, meanwhile messenger RNA levels of transforming growth factor-β1 (TGF-β1) was determined using RT-PCR.Results1. Compared with other groups, the inflammatory cell infiltration and collagen increasing were observed in the model group. The content of lipase and amylase were significantly decreased (P<0.05);2. Compared with other groups, the expression of collagen I,α-SMA mRNA,Fn mRNA and proteinα-SMA were all increased (P<0.01)in model group.3. Compared with the model group , the pancreatic tissue pathology score,collagen deposition and the expression of TGF-β1 mRNA were decreased, while amylase ( 7347.81±101.93U/g ) and lipase(14135.25±1272.10U/g)were significantly increased in the treatment group (P<0.05).Conclusion1. Combined with long-term ethanol intaking, intraperitoneal injection of LPS can induce rat chronic pancreatitis.2. Combined with long-term ethanol intaking, intraperitoneal injection of LPS can activate the PSCs, raise the expression ofα-SMA and induce pancreatic fibrosis.3. Curcumin has an anti-fibrosis effect on chronic pancreatitis induced by ethanol combined with LPS. The anti-fibrosis mechanism is possibly related to its inhibitory effect on the production of TGF-β1. |
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