白僵蚕水提物对镉致胰岛β细胞毒性的影响研究

目的 探讨白僵蚕水提物对硫酸镉（CdSO4）致胰岛β细胞NIT-1细胞毒性的影响。方法 采用冷水浸泡法提取白僵蚕的水溶性成分。分别用（0、0.4、0.8、1.6、3.2和6.4mg/mL）白僵蚕水提物染毒细胞24h；用4μmol/L CdSO4分别与（0.4和0.8mg/mL）白僵蚕水提物混合后共处理24h；以及用（0.4和0.8mg/mL） 白僵蚕水提物预处理2h，再以4μmol/L CdSO4分别染毒24h。采用CCK8、Hoechst33258染色以及荧光探针等方法分别检测NIT-1细胞存活率、细胞凋亡及活性氧ROS的水平。结果 （1）与对照组比较，细胞存活率随白僵蚕水提物染毒浓度的增加呈现出先升高后下降的趋势（P<0.05）；（2）与单独处理组相比，4μmol/L CdSO4与（0.4和0.8mg/mL）白僵蚕水提物共处理组细胞存活率均降低（P<0.05），且预处理组细胞存活率相比白僵蚕单独处理组也降低（P<0.05）；（3）联合处理组细胞变圆、细胞核呈致密浓染，细胞凋亡率均高于白僵蚕和CdSO4单染组（P<0.05）；同时，联合处理组ROS荧光强度也升高，分别为白僵蚕和CdSO4单染组的1.18和1.05倍（P<0.05）。结论 白僵蚕水提物在低浓度下可促进NIT-1细胞的增殖，高浓度则降低细胞的存活率；低浓度的白僵蚕水提物无法拮抗CdSO4诱导的细胞死亡，反而增强了细胞毒性，其机制可能与凋亡和ROS水平增加有关。

Effects of water-soluble extracts from bombyx batryticatus on cadmium-induced cytotoxicity of pancreatic islet beta cell

Objective To explore the effects of water-soluble extracts from Bombyx batryticatus on the cytotoxicity of NIT-1 pancreatic islet beta cells induced by cadmium sulfate(CdSO4). Methods The cold water immersion method was used to extract the water-soluble components of Bombyx batryticatus. The cells were exposed to 0, 0.4, 0.8, 1.6, 3.2 and 6.4 mg/mL water-soluble extracts from Bombyx batryticatus for 24 h respectively, then 4 μmol/L CdSO4 was mixed with 0.4 and 0.8 mg/mL water-soluble extracts from Bombyx batryticatus for 24 h. And 0.4 and 0.8 mg/mL water-soluble extracts from Bombyx batryticatus was pretreated for 2 h, and then exposed to 4 μmol/L CdSO4 for 24 h. The viability rate, apoptosis and ROS level were separately detected by CCK8, Hoechst33258 staining and fluorescence probe. Results Compared with the control group, the cell survival rate increased at first and then decreased with the increase of the concentration of the water-soluble components of Bombyx batryticatus(P<0.05). Compared with the treatment group alone, the cell viability rate of 4 μmol/L CdSO4 and 0.4 and 0.8 mg/mL water-soluble components of Bombyx batryticatus co-treatment group decreased(P<0.05). And the cell viability rate of pretreatment group also decreased(P<0.05) compared with treatment group alone. The cells in the combined treatment group became round and the nucleus was densely stained, and the apoptosis rate was higher than that of the water-soluble components of Bombyx batryticatus and CdSO4 single staining group(P<0.05). The fluorescence intensity of ROS in the co-treatment group was also increased, which was 1.18 and 1.05 times of which in the Bombyx batryticatus and CdSO4 single treatment group, respectively. Conclusion Low concentrations of Bombyx batryticatus water extracts can promote the NIT-1 cell proliferation, while high concentrations are able to decrease the survival rate of cells. The low concentrations of the aqueous extracts of Bombyx batryticatus are failure to antagonize the death of CdSO4-induced cell, on the contrary, enhance cytotoxicity, which may be related to the increase of apoptosis and ROS levels.