Investigation of the effect of L-theanine on the hippocampus tissue and serumbdnf and adipocytokine levels in diabetic rats

Diabetes Mellitus (DM), a metabolic disease characterized by the increased blood glucose level, insulin deficiency or ineffectiveness, may cause structural and functional disorders in the brain. L-Theanine (LTN) is a unique amino acid found in Camellia sinensis plant tea species, with its relaxing, psychoactive, antidepressant, antiinflammatory and antinecrotic properties, and regulating the functions of the brain and hippocampus which is the part of the brain related to memory and learning. In our study, the effect of LTN on the levels of BDNF and adipocytokines (TNF-α, leptin, adiponectin and resistin) in the hippocampus tissue and serum of rats which got diabetes via nicotinamide (NA)/streptozotocin (STZ) as well as tissue histopathology was evaluated. For this purpose, 32 male Wistar rats (150-250 g) were divided into four groups (n=8/group) as control, LTN, DM and DM+LTN. Drinking water was given to the control and DM groups by gastric gavage for 28 days, and 200 mg/kg/day LTN to the LTN and DM+LTN groups. Determinations in tissue homogenates and sera were made with commercial ELISA kits. The leptin and adiponectin levels in the hippocampus tissue were found to be significantly lower in the DM+LTN group compared to the DM group (p<0.05). Although there were changes in other parameters, no statistical difference was found (p>0.05). In histopathological analysis, although the damage was reduced in all sections of the hippocampus, this change was significant in the CA3 region (p<0.05). Although LTN exhibits protective effects in DM from degeneration of the hippocampus tissue, it can also affect the levels of BDNF and adipocytokines. Keywords: Adipocytokine, diabetes, ELISA, hippocampus, L-Theanine