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Objective To investigate the effects of Epigallocatechin gallate(EGCG)on IL-1βinduced MIN6 cells apoptosis. M.Methods The experiment group was divided into control group,IL-1β group,IL-1β+ EGCG low concentration group and IL-1β+EGCG high concentration group.Cell activity was detected by CCK8.Insulin secretion was detected by ELISA.cell apoptosis was detected by flow cytometry.The mitochondrial membrane potential was detected by flow cytometry.ATP content and cell ac-tivity of ROS were detected by colorimetry and chemiluminescence method.Results Compared with normal group,IL-1β group showed much lower cell activity,insulin secretion,cell mitochondrial membrane potential and ATP content,and at the same time IL-1βgroup had significantly higher cell apoptosis and ROS activities.After given EGCG,both low concentration group and high con-centration group had higher cell activity,insulin secretion,cell mitochondrial membrane potential and ATP content,at the same time lower cell apoptosis and ROS activities was showed.And the IL-1β+EGCG high concentration group worked more powerful.Con-clusion EGCG has protective effects on IL-1βinduced MIN6 cells apoptosis.Its mechanism may be related to increasing the content of the ATP and mitochondrial membrane potential and protecting mitochondrial function as well reducing the activity of ROS.
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Objective To investigate the protective role of FDP to STZ induced islest apoptosis and the potential mechanisms.Methods The pancreases of the rats were treated to collect islets cells.The cells were incubated with STZ with/or FDP.Cell morphology,insulin secretion,HO-1 activity,CO content,SOD activity,GSH-px activity,iNOS activity were examined.No conetent and apoptotic percentage was detected.Results HO-1 activity and CO content of the normal control group were low.STZ induced a significant decrease of cell activity and insulin release,flow cytometry analysis showed that apoptotic percentage of islet cells remarkably increased following the addition of STZ,FDP obviously improved the islets cellular activity damaged by STZ,basic amount of insulin secretion and stimulated by high glucose were improved(P
ABSTRACT
BACKGROUND: Fructose-1,6-diphosphate (FDP) of certain dosage plays a protective role in the pancreatic islets damaged by interleukin-1 beta (IL-1β), and there are different effects of FDP of low and high dosages.OBJECTIVE: To investigate the effects of FDP of low and high dosages on the islet cells damaged by IL-1β.DESIGN: A grouped design and controlled animal experiment.SETTING: Department of Physiology, North Sichuan Medical College.MATERIALS: The experiments were carried out in the Tumor Laboratory and Central Laboratory of Rheumatology and Immunology, Department of Surgery, North Sichuan Medical College between July 2004 and February 2006. Twenty Wistar rats within 1-3 days after birth were selected.METHODS: The pancreases of the rats were removed to collect islet cells, and then the cells were divided into normal control group, IL-1β damaged group, IL-1β+1, 25, 50 mmol/L FDP groups. The cellular activity was detected with methyl-thiazol-tetrazolium (MTT) assay, basic amount of insulin secretion and that stimulated by high glucose with radioimmunoassay, content of nitric oxide and activity of nitric oxide synthase (NOS) with nitric oxide and NOS kits, and the with [Ca2+]i with Fura-2fluorescent assay.MAIN OUTCOME MEASURES: Activity of islet cells; basic amount of insulin secretion and that stimulated by high glucose; content of nitric oxide and activity of NOS; [Ca2+]i.RESULTS: ① The activities (A values) of the islet cells in the IL-1β damaged group, IL-1β+1, 25, 50 mmol/L FDP groups were obviously lower than that in the normal control group (0.116±0.012, 0.129±0.008, 0.125±0.015, 0.120±0.016, 0.252±0.020, P ＜ 0.01). The activities (A values) of the islet cellswere not significantly different from that in the IL-1β damaged group (P ＞ 0.05) when the FDP dosage was too low (1 mmol/L) or too high (25 mmol/L). ② The basic amount of insulin secretion and that stimulated by glucose were significantly lower in the IL-1β damaged group, IL-1β+1, 25, 50 mmol/L FDP groups than in the normal control group [(237.00±22.21), (230.83±11.58), (225.16±12.46), (220.50±15.63),(425.67 ±16.85) mIU/L; (90.17 ±6.11), (96.62 ±8.64), (87.66-±8.24),(85.46±9.59), (204.50±10.78) mIU/L, P ＜ 0.01], and there were no significant differences between the FDP groups of Iow and high dosages and the IL-1β damaged group (P ＞ 0.05). ③ The NOS activity and content of nitric oxide in the supernatant were obviously higher in the IL-1β damaged group than in the normal control group [(332.07±25.34), (144.86±12.17) μkat/L;(457.64±19.29), (84.67±10.23) μmol/L, P ＜ 0.01], and those in the IL-1β+1, 25, 50 mmol/L FDP groups were not significantly different from those in the IL-1β damaged group. ④ The [Ca2+]i concentration in islet cells was obviously higher in the IL-1β damaged group than in the norrmal control group [(328.50±26.28), (73.42±1.79) nmol/L, P ＜ 0.01], but obviously lower in the IL-1β+1, 25, 50 mmol/L FDP groups than in the IL-1β damaged group [(152.72± 11.86), (216.39±15.32), (233.61±21.76),(328.50±26.28) nmol/L, P ＜ 0.01].CONCLUSION: FDP of low and high dosages can not protect the islet cells damaged by IL-1β.