Chlorogenic acid may improve memory function and decrease inflamation of frontal lobe in diabetic rat

INTRODUCTION: Diabetes Mellitus (DM) is a chronic disease with many complications, one of which is diabetic encephalopathy which is characterised by memory dysfunction. Hyperglycaemia that occurs in DM will activate inflammatory pathways in neurons, including NF-κB pathway. Activation of this pathway produce proinflammatory agents such as MCP-1 and IL-6, which activate glial cells. Activation of glial cells is characterised by Glial Fibrillary Acid Protein (GFAP). Chlorogenic acid (CGA) has been reported to have anti-inflammatory effects and can improve memory function. This research aimed to determine the effect of CGA as anti-inflammation, its effect on memory function, mRNA expression of NF-κB, MCP-1, IL- 6, and GFAP of frontal lobe.

MATERIALS AND METHODS: A total of 24 male rats were randomly divided into six groups: control, DM 1.5 month (DM1.5), DM 2 months (DM2) and the group with three different doses of CGA 12.5 (CGA1), 25 (CGA2), and 50 (CGA3) mg/KgBW. Frontal lobe tissue is taken for analysis of mRNA expression for NF-κB, MCP-1, IL-6, and GFAP using Reverse Transcriptase PCR (RT-PCR). Samples were also taken for histopathology preparation and stained by immunohistochemistry method using anti-GFAP antibodies to observe glial cell activation in frontal lobe tissue.

RESULTS: The group that was given CGA at all doses have statistically significant better memory function, i.e. DM2 versus CGA1 (p = 0.036), CGA2 (p = 0.040), and CGA3 (p = 0.021). The result of mRNA expression in NF-κB was lower in the group given CGA, i.e. DM2 compared to CGA2 (p = 0.007). mRNA expression of MCP-1 was significantly lower in all CGA treatment groups compared to the non-CGA group (p = 0.000). IL-6 mRNA expression was lower than the group not given CGA, DM compared to CGA2 (p = 0.028). GFAP mRNA expression was lower than the group given CGA in DM, DM2 group compared to CGA1 (p = 0.04) and CGA3 (p = 0.004).

CONCLUSION: Administration of CGA can improve memory function at all doses given, and can reduce brain inflammatory activity, especially in the CGA2 group.