[Effect of emodin on pancreatic fibrosis: experiment with rats]

To study the effect of emodin on pancreatic fibrosis and potential mechanism thereof.

Fifty SD rats were randomly divided into 5 equal groups: normal control group, model control group, low-dose emodin-treated group, mediate-dose emodin-treated group, and high-dose emodin-treated group. The rats of the latter 4 groups underwent infusion of trinitrobenzene sulfonic acid (TNBS) into the pancreatic duct so as to establish models of pancreatic fibrosis. The emodin-treated rats were fed with different doses of emodin (20, 40, and 80 mg/kg body weight), while the normal and model control groups received 0.9% sodium chloride solution instead. Twenty-eight days later the rats were killed, blood samples were collected, and their pancreases were taken out. The serum levels of hyaluronic acid (HA) and laminin (LN) were determined by radioimmunoassay. The histopathological alterations were studied by optical microscopy. The expression of collagen was examined by Van Gieson staining. Western blotting was used to detect the protein expression of transforming growth factor-beta(1) (TGF-beta(1)).

(1) The serum level of HA of the low-dose, mediate-dose, and high-dose emodin-treated groups were 87 microg/L +/- 22 microg/L, 78 microg/L +/- 25 microg/L, and 62 microg/L +/- 19 microg/L respectively, all significantly lower than that of the model control group (113 microg/L +/- 27 microg/L, P < 0.05 or < 0.01). The serum levels of laminin in the low-dose, mediate-dose, and high-dose emodin-treated groups were 67 microg/L +/- 14 microg/L, 57 microg/L +/- 12 microg/L, and 44 microg/L +/- 10 microg/L respectively, all significantly lower than that of the model control group (86 microg/L +/- 17 microg/L, P < 0.05 or P < 0.01); (2) The degrees of fibrosis of the emodin-treated groups were obviously ameliorated in comparison with the model control group, the higher the dose of emodin the more improved the pathological changes, especially in the high-dose emodin-treated group (P < 0.05). (3) The percentages of collagen positive cells of the low-dose, mediate-dose, and high-dose emodin-treated groups were 39% +/- 7%, 38% +/- 4%, and 36% +/- 5% respectively, all lower than that of the model control group (42% +/- 6%), with a significant difference between the high-dose emodin-treated group and the model control group (P < 0.05). (4) The protein content of TGF-beta(1) of the low-dose, mediate-dose, and high-dose emodin-treated groups were 44.3% +/- 2.1%, 39.2% +/- 1.8%, and 28.8% +/- 1.6% respectively, all significantly lower than that of the model control group (60.7% +/- 1.7%, all P < 0.05), and the protein content of TGF-beta(1) of the high-dose emodin-treated group was significantly lower than those of the other 2 emodin-treated groups (both P < 0.05).

Emoidn has an anti-fibrosis effect on pancreatic fibrosis, which maybe related to the content of TGF-beta(1) protein.