AIM: To investigate the role of epidermal growth factor(EGF) in visceral hypersensitivity and its effect on the serotonin transporter(SERT).METHODS: A rat model for visceral hypersensitivity was established by intra-c...AIM: To investigate the role of epidermal growth factor(EGF) in visceral hypersensitivity and its effect on the serotonin transporter(SERT).METHODS: A rat model for visceral hypersensitivity was established by intra-colonic infusion of 0.5% acetic acid in 10-d-old Sprague-Dawley rats. The visceral sensitivity was assessed by observing the abdominal withdrawal reflex and recording electromyographic activity of the external oblique muscle in response to colorectal distension. An enzyme-linked immunosorbent assay was used to measure the EGF levels in plasma and colonic tissues. SERT mRNA expression was detected by real-time PCR while protein level was determined by Western blot. The correlation between EGF and SERT levels in colon tissues was analyzed by Pearson's corre-lation analysis. SERT function was examined by tritiated serotonin(5-HT) uptake experiments. Rat intestinal epithelial cells(IEC-6) were used to examine the EGF regulatory effect on SERT expression and function via the EGF receptor(EGFR).RESULTS: EGF levels were significantly lower in th rats with visceral hypersensitivity as measured in plas ma(2.639 ± 0.107 ng/mL vs 4.066 ± 0.573 ng/mL, < 0.01) and in colonic tissue(3.244 ± 0.135 ng/10 mg vs 3.582 ± 0.197 ng/100 mg colon tissue, P 0.01) compared with controls. Moreover, the EGF leve were positively correlated with SERT levels(r = 0.820 P < 0.01). EGF displayed dose- and time-dependen increased SERT gene expressions in IEC-6 cells. A EGFR kinase inhibitor inhibited the effect of EGF o SERT gene upregulation. SERT activity was enhance following treatment with EGF(592.908 ± 31.515 fmo min per milligram vs 316.789 ± 85.652 fmol/min pe milligram protein, P < 0.05) and blocked by the EGF kinase inhibitor in IEC-6 cells(590.274 ± 25.954 fmo min per milligram vs 367.834 ± 120.307 fmol/min pe milligram protein, P < 0.05).CONCLUSION: A decrease in EGF levels may contribute to the formation of visceral hypersensitivity through downregulation of SERT-mediated 5-HT uptake into enterocytes.展开更多
OBJECTIVE Compound Kushen injection(CKI)is a bis-herbal formulation extracted from Kushen(Radix Sophorae Flavescentis)and Baituling(Rhizoma Heterosmilacis Japonicae).Clinically,it is used as the adjuvant treatment of ...OBJECTIVE Compound Kushen injection(CKI)is a bis-herbal formulation extracted from Kushen(Radix Sophorae Flavescentis)and Baituling(Rhizoma Heterosmilacis Japonicae).Clinically,it is used as the adjuvant treatment of cancer.However,with the increased application,the cases of immediate hypersensitivity reactions(IHRs)also gradually rise.In this study,we investigated the underlying mechanism(s)and active constituent(s)for CKI-induced IHRs in experimental models.METHODS T helper 2(Th2)immunity-amplified mice were prepared by aluminum adjuvant.Anaphylactic shock was detected by measuring rectal thermometry in propranolol pretreated mice.For evaluating microvascular permeability,Evans blue extravasation assay was used.Platelet-activating factor(PAF),serum total IgE(tIgE)and mouse mast cell protease 1(MMCP1)were measured by ELISA.RESULTS The obtained results showed that CKI did not elevate serum tIgE and MMCP1 after consecutive immunization for five weeks,but could induce Evans blue extravasation(local)and cause obvious hypothermia(systemic)after a single injection.Further study showed that alkaloids in Kushen,especially matrine,were responsible for CKI-induced IHRs.Mechanism study showed that various PAF receptor antagonists could significantly counter CKI-induced IHRs locally or systemically.In cell system,CKI was able to promote PAF production in a non-cell-selective manner.In cell lysate,the effect of CKI on PAF production became stronger and could be abolished by blocking de novo pathway.CONCLUSION In conclusion,our study identifies,for the first time,that CKI is a PAF inducer.It causes non-immunologic IHRs,rather than IgE-dependent IHRs,by promoting PAF production through de novo pathway.Alkaloids in Kushen,especially matrine,are the prime culprits for IHRs.Our findings may provide a potential approach for preventing and treating CKI-induced IHRs.展开更多
基金Supported by National Natural Science Foundation of China,No.81270469Key Medical Personnel of Jiangsu Province,No.RC2011063m
文摘AIM: To investigate the role of epidermal growth factor(EGF) in visceral hypersensitivity and its effect on the serotonin transporter(SERT).METHODS: A rat model for visceral hypersensitivity was established by intra-colonic infusion of 0.5% acetic acid in 10-d-old Sprague-Dawley rats. The visceral sensitivity was assessed by observing the abdominal withdrawal reflex and recording electromyographic activity of the external oblique muscle in response to colorectal distension. An enzyme-linked immunosorbent assay was used to measure the EGF levels in plasma and colonic tissues. SERT mRNA expression was detected by real-time PCR while protein level was determined by Western blot. The correlation between EGF and SERT levels in colon tissues was analyzed by Pearson's corre-lation analysis. SERT function was examined by tritiated serotonin(5-HT) uptake experiments. Rat intestinal epithelial cells(IEC-6) were used to examine the EGF regulatory effect on SERT expression and function via the EGF receptor(EGFR).RESULTS: EGF levels were significantly lower in th rats with visceral hypersensitivity as measured in plas ma(2.639 ± 0.107 ng/mL vs 4.066 ± 0.573 ng/mL, < 0.01) and in colonic tissue(3.244 ± 0.135 ng/10 mg vs 3.582 ± 0.197 ng/100 mg colon tissue, P 0.01) compared with controls. Moreover, the EGF leve were positively correlated with SERT levels(r = 0.820 P < 0.01). EGF displayed dose- and time-dependen increased SERT gene expressions in IEC-6 cells. A EGFR kinase inhibitor inhibited the effect of EGF o SERT gene upregulation. SERT activity was enhance following treatment with EGF(592.908 ± 31.515 fmo min per milligram vs 316.789 ± 85.652 fmol/min pe milligram protein, P < 0.05) and blocked by the EGF kinase inhibitor in IEC-6 cells(590.274 ± 25.954 fmo min per milligram vs 367.834 ± 120.307 fmol/min pe milligram protein, P < 0.05).CONCLUSION: A decrease in EGF levels may contribute to the formation of visceral hypersensitivity through downregulation of SERT-mediated 5-HT uptake into enterocytes.
文摘OBJECTIVE Compound Kushen injection(CKI)is a bis-herbal formulation extracted from Kushen(Radix Sophorae Flavescentis)and Baituling(Rhizoma Heterosmilacis Japonicae).Clinically,it is used as the adjuvant treatment of cancer.However,with the increased application,the cases of immediate hypersensitivity reactions(IHRs)also gradually rise.In this study,we investigated the underlying mechanism(s)and active constituent(s)for CKI-induced IHRs in experimental models.METHODS T helper 2(Th2)immunity-amplified mice were prepared by aluminum adjuvant.Anaphylactic shock was detected by measuring rectal thermometry in propranolol pretreated mice.For evaluating microvascular permeability,Evans blue extravasation assay was used.Platelet-activating factor(PAF),serum total IgE(tIgE)and mouse mast cell protease 1(MMCP1)were measured by ELISA.RESULTS The obtained results showed that CKI did not elevate serum tIgE and MMCP1 after consecutive immunization for five weeks,but could induce Evans blue extravasation(local)and cause obvious hypothermia(systemic)after a single injection.Further study showed that alkaloids in Kushen,especially matrine,were responsible for CKI-induced IHRs.Mechanism study showed that various PAF receptor antagonists could significantly counter CKI-induced IHRs locally or systemically.In cell system,CKI was able to promote PAF production in a non-cell-selective manner.In cell lysate,the effect of CKI on PAF production became stronger and could be abolished by blocking de novo pathway.CONCLUSION In conclusion,our study identifies,for the first time,that CKI is a PAF inducer.It causes non-immunologic IHRs,rather than IgE-dependent IHRs,by promoting PAF production through de novo pathway.Alkaloids in Kushen,especially matrine,are the prime culprits for IHRs.Our findings may provide a potential approach for preventing and treating CKI-induced IHRs.
