Inhibitory Effect of CCK-8 on Methamphetamine-Induced Apoptosis / 法医学杂志

OBJECTIVES@#To investigate the inhibitory effect of cholecystokinin octapeptide (CCK-8) binding to cholecystokinin 2 receptor (CCK2R) on methamphetamine (METH)-induced neuronal apoptosis, and to explore the signal transduction mechanism of β-arrestin 2 in CCK-8 inhibiting METH-induced neuronal apoptosis.@*METHODS@#SH-SY5Y cell line was cultured, and HEK293-CCK1R and HEK293-CCK2R cell line were constructed by lentivirus transfection. Small interfering RNA (siRNA) was used to knockdown the expression of β-arrestin 2. Annexin Ⅴ-FITC/PI staining and flow cytometry were used to detect the apoptotic rate of cells, and Western blotting was used to detect the expression of apoptosis-related proteins.@*RESULTS@#The apoptosis of SH-SY5Y cells was induced by 1 mmol/L and 2 mmol/L METH treatment, the number of nuclear fragmentation and pyknotic cells was significantly increased, and the expression of apoptosis-related proteins Bax and cleaved caspase-3 were increased. CCK-8 pre-treatment at the dose of 0.1 mmol/L and 1 mmol/L significantly reversed METH-induced apoptosis in SH-SY5Y cells, and inhibited cell nuclear fragmentation, pyknosis and the changes of apoptosis-related proteins induced by METH. In lentivirus transfected HEK293-CCK1R and HEK293-CCK2R cells, the results revealed that CCK-8 had no significant effect on METH-induced changes of apoptosis-related proteins in HEK293-CCK1R cells, but it could inhibit the expression level of apoptosis-related proteins in HEK293-CCK2R cells induced by METH. The inhibitory effect of CCK-8 on METH-induced apoptosis was blocked by the knockdown of β-arrestin 2 expression in SH-SY5Y cells.@*CONCLUSIONS@#CCK-8 can bind to CCK2R and exert an inhibitory effect on METH-induced apoptosis by activating the β-arrestin 2 signal.

Weak Iaser effects on the biocompatibiIity of chitosan and Nafion as impIantabIe gIucose sensor outer materiaIs / 中国组织工程研究

BACKGROUND: The biocompatibility of chitosan and Nafion can be improved by external factors. OBJECTIVE: To explore the effect of different weak laser irradiations (red, blue, green) on biocompatibility of porous chitosan membrane and the Nafion membrane. METHODS: (1) Porous chitosan membrane test: Forty-eight Sprague-Dawley rats were randomized into red, green, blue light groups (n=16 per group). Porous chitosan membranes (two membranes at each side) were implanted into the bilateral subcutaneous tissue of the rat back with the spine as the axis of symmetry, and then the four implanted membranes in each rat were irradiated by red light for 0, 2, 4, 6 minutes respectively. The irradiation lasted until sample collection at 7, 14, 28 and 56 days after implantation, and the samples were used for histological analysis. The same procedures were done in the blue and green light groups. (2) Nafion membrane test: Twenty-four Sprague-Dawley rats were randomized into red, blue and green light groups (n=8 per group). Nafion membranes (two membranes at each side) were implanted into the bilateral subcutaneous tissue of the rat back with the spine as the axis of symmetry, and then the four implanted membranes in each rat were irradiated by red light for 0, 2, 4, 6 minutes respectively. The irradiation lasted until sample collection at 7 and 14 days after implantation, and the samples were used for histological analysis. The same procedures were done in the blue and green light groups. RESULTS AND CONCLUSION: The content of red blood cells in blood vessels and vascular density around the membrane materials (porous chitosan membranes and Nafion membranes) increased after irradiated by red light (especially at 7 days after implantation); the red light had less influence on the inflammatory response and fibrous capsule thickness around the two kinds of membranes. The inflammatory cells percentage around the membrane materials irradiated by green light for 4 minutes was significantly reduced, and the blue light had less influence on inflammatory responses; blue and green lights showed effects on the fibrous capsule thickness and vascular density around the membrane materials, but the effect was not obvious. Thus, to a certain extent, weak lasers can improve the biocompatibility of PCSM and Nafion membrane.