摘要Background::Pancreatic stellate cells (PSCs) activation plays a critical role in the development of chronic pancreatitis. Previous studies confirmed that thromboxane A2 receptor (TxA 2r) was overexpressed in activated PSCs in rats. The purpose of this study was to investigate the role of TxA 2r in the activation of PSCs induced by 8-epi-prostaglandin F 2α (8-epi-PGF 2α). Methods::TxA 2r expression in both quiescent and activated PSCs was detected by immunocytochemistry and immunoblot assay. Isolated PSCs were treated with 8-epi-PGF 2α (10 -6, 10 -7, 10 -8 mol/L) for 48 h, and SQ29548 (10 -4, 10 -6, and 10 -7 mol/L), a TxA 2r-specific antagonist, for 48 h, respectively, to identify the drug concentration with the best biological effect and the least cytotoxicity. Then isolated PSCs were treated with SQ29548 (10 -4 mol/L) for 2 h, followed by 10 -7 mol/L 8-epi-PGF 2α for 48 h. Real-time polymerase chain reaction was performed to detect the messenger RNA (mRNA) levels of α-smooth muscle actin (α-SMA) and collagen I. Comparisons between the groups were performed using Student’s t test. Results::TxA 2r was up-regulated in activated PSCs in vitro compared with quiescent PSCs (all P < 0.001). Compared with the control group, different concentrations of 8-epi-PGF 2a significantly increased mRNA levels of α-SMA (10 -6 mol/L: 2.23 ± 0.18 vs. 1.00 ± 0.07, t= 10.70, P < 0.001; 10 -7 mol/L: 2.91 ± 0.29 vs. 1.01 ± 0.08, t= 10.83, P <0.001; 10 -8 mol/L, 1.67 ± 0.07 vs. 1.00 ± 0.08, t= 11.40, P < 0.001) and collagen I (10 -6 mol/L: 2.68 ± 0.09 vs. 1.00 ± 0.07, t = 24.94, P < 0.001; 10 -7 mol/L: 2.12 ± 0.29 vs. 1.01 ± 0.12 , t = 6.08, P < 0.001; 10 -8 mol/L: 1.46 ± 0.15 vs. 1.00 ± 0.05, t = 4.93, P = 0.008). However, different concentrations of SQ29548 all significantly reduced the expression of collagen I (10 -4 mol/L: 0.55 ± 0.07 vs. 1.00 ± 0.07, t = 10.47, P < 0.001; 10 -6 mol/L: 0.56 ± 0.10 vs. 1.00 ± 0.07, t = 6.185, P < 0.001; 10 -7 mol/L: 0.27 ± 0.04 vs. 1.00 ± 0.07, t= 15.41, P < 0.001) and α-SMA (10 -4 mol/L: 0.06 ± 0.01 vs. 1.00 ± 0.11, t= 15.17, P < 0.001; 10 -6 mol/L: 0.28 ± 0.03 vs. 1.00 ± 0.11, t= 11.29, P < 0.001; 10 -7 mol/L: 0.14 ± 0.04 vs. 1.00 ± 0.11, t= 12.86, P < 0.001). After being treated with SQ29548 (10 -4 mol/L) and then 8-epi-PGF 2α (10 -7 mol/L), the mRNA levels of a-SMA (0.20 ± 0.08 vs. 1.00 ± 0.00, t= 17.46, P < 0.001) and collagen I (0.69 ± 0.13 vs. 1.00 ± 0.00, t = 4.20, P = 0.014) in PSCs were significantly lower than those of the control group. Conclusions::The results show that 8-epi-PGF 2α promoted PSCs activation, while SQ29548 inhibited PSCs activation induced by 8-epi-PGF 2α. The result indicated that TxA 2r plays an important role during PSC activation and collagen synthesis induced by 8-epi-PGF 2αin vitro. This receptor may provide a potential target for more effective antioxidant therapy for pancreatic fibrosis.

abstractsBackground::Pancreatic stellate cells (PSCs) activation plays a critical role in the development of chronic pancreatitis. Previous studies confirmed that thromboxane A2 receptor (TxA 2r) was overexpressed in activated PSCs in rats. The purpose of this study was to investigate the role of TxA 2r in the activation of PSCs induced by 8-epi-prostaglandin F 2α (8-epi-PGF 2α). Methods::TxA 2r expression in both quiescent and activated PSCs was detected by immunocytochemistry and immunoblot assay. Isolated PSCs were treated with 8-epi-PGF 2α (10 -6, 10 -7, 10 -8 mol/L) for 48 h, and SQ29548 (10 -4, 10 -6, and 10 -7 mol/L), a TxA 2r-specific antagonist, for 48 h, respectively, to identify the drug concentration with the best biological effect and the least cytotoxicity. Then isolated PSCs were treated with SQ29548 (10 -4 mol/L) for 2 h, followed by 10 -7 mol/L 8-epi-PGF 2α for 48 h. Real-time polymerase chain reaction was performed to detect the messenger RNA (mRNA) levels of α-smooth muscle actin (α-SMA) and collagen I. Comparisons between the groups were performed using Student’s t test. Results::TxA 2r was up-regulated in activated PSCs in vitro compared with quiescent PSCs (all P < 0.001). Compared with the control group, different concentrations of 8-epi-PGF 2a significantly increased mRNA levels of α-SMA (10 -6 mol/L: 2.23 ± 0.18 vs. 1.00 ± 0.07, t= 10.70, P < 0.001; 10 -7 mol/L: 2.91 ± 0.29 vs. 1.01 ± 0.08, t= 10.83, P <0.001; 10 -8 mol/L, 1.67 ± 0.07 vs. 1.00 ± 0.08, t= 11.40, P < 0.001) and collagen I (10 -6 mol/L: 2.68 ± 0.09 vs. 1.00 ± 0.07, t = 24.94, P < 0.001; 10 -7 mol/L: 2.12 ± 0.29 vs. 1.01 ± 0.12 , t = 6.08, P < 0.001; 10 -8 mol/L: 1.46 ± 0.15 vs. 1.00 ± 0.05, t = 4.93, P = 0.008). However, different concentrations of SQ29548 all significantly reduced the expression of collagen I (10 -4 mol/L: 0.55 ± 0.07 vs. 1.00 ± 0.07, t = 10.47, P < 0.001; 10 -6 mol/L: 0.56 ± 0.10 vs. 1.00 ± 0.07, t = 6.185, P < 0.001; 10 -7 mol/L: 0.27 ± 0.04 vs. 1.00 ± 0.07, t= 15.41, P < 0.001) and α-SMA (10 -4 mol/L: 0.06 ± 0.01 vs. 1.00 ± 0.11, t= 15.17, P < 0.001; 10 -6 mol/L: 0.28 ± 0.03 vs. 1.00 ± 0.11, t= 11.29, P < 0.001; 10 -7 mol/L: 0.14 ± 0.04 vs. 1.00 ± 0.11, t= 12.86, P < 0.001). After being treated with SQ29548 (10 -4 mol/L) and then 8-epi-PGF 2α (10 -7 mol/L), the mRNA levels of a-SMA (0.20 ± 0.08 vs. 1.00 ± 0.00, t= 17.46, P < 0.001) and collagen I (0.69 ± 0.13 vs. 1.00 ± 0.00, t = 4.20, P = 0.014) in PSCs were significantly lower than those of the control group. Conclusions::The results show that 8-epi-PGF 2α promoted PSCs activation, while SQ29548 inhibited PSCs activation induced by 8-epi-PGF 2α. The result indicated that TxA 2r plays an important role during PSC activation and collagen synthesis induced by 8-epi-PGF 2αin vitro. This receptor may provide a potential target for more effective antioxidant therapy for pancreatic fibrosis.