Effects of fructose-1,6-diphosphate of low and high dosages on islet cells damaged by interleukin-1 beta / 中国组织工程研究

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.