Modulation of curcumin on PERK- CHOP signaling pathway in pancreas of type 2 diabetic rats

Author(s): Kaijian Hou*, Kapil Kumar, Barkat Ali Khan, Xuhuang Wang, Chao Chen, Bangtai Wu & Yuanyuan Guo

Objective: To investigate whether curcumin can decrease blood glucose by affecting the PERK- CHOP signaling pathway in pancreas.

Methods: A total of 45 male SD rats were randomly divided into normal control group, diabetes model group and curcumin treatment group, 15 rats in each group. The rat was given high fat as well as high sugar diet and intraperitoneal injection of streptozotocin (35 mg/kg, twice, once /d) to establish type 2 diabetes rat model with the model success level as “fasting glucose ≥ 11. 1 mmol /L. After the model was successfully established, the rats in curcumin treatment group were treated with curcumin through gastric tube for 30 days at 200 mg/ kg per day. ELISA method was adopted to detect serum adiponectin level, glucose oxidase method was applied to measure blood glucose and Western blotting as well as Real-time PCR method were respectively used to detect the key molecules of PERK- CHOP expression of PERK, CHOP protein, signaling pathway, and mRNA.

Results: Compared with normal control group, the blood glucose level was significantly higher and serum adiponectin level significantly lower in diabetes model group (P<0.05); compared with diabetes model group, the blood glucose level of curcumin treatment group decreased significantly and serum adiponectin level significantly increased (P<0.05). The content of PERK and CHOP mRNA in pancreatic tissue of diabetes group significant increased compared with normal control group (P<0.05) and compared with diabetes group, the expression of PERK and CHOP mRNA in curcumin treatment group was lower (P<0.05).

Conclusion: Curcumin can down regulate expression of PERK and CHOP in the pancreas of diabetic rats, correct the abnormality of PERK-CHOP signal transduction pathway during diabetes and it can also play a role in lowering blood glucose by enhancing the level of adiponectin, the sensitivity of target tissues to insulin as well as the level of adiponectin.

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