Fermenting soybeans with Bacillus licheniformis potentiates their capacity to improve cognitive function and glucose homeostaisis in diabetic rats with experimental Alzheimer’s type dementia

Diabetes is a group of metabolic disorders with an increased risk of developing cognitive impairment and dementia. The hippocampus in the forebrain contains an abundance of insulin receptors related to cognitive function and plays an important role in the pathophysiology of neurodegenerative disorders. Berberine from traditional Chinese medicine has been used to treat diabetes and diabetic cognitive impairment, although its related mechanisms are largely unknown. In this study, a STZ diabetes rat model feeding with a high-fat diet was used to test the effects of berberine compared with metformin. Oral glucose tolerance and hyperinsulinemic-euglycemic clamp were used for glucose metabolism and insulin resistance. The Morris water maze was used to observe the compound effects on cognitive impairment. Serum and hippocampal [Formula: see text]-amyloid peptide (A[Formula: see text], Tau and phosphorylated Tau protein deposition in the hippocampi were measured. The TUNEL assay was used to detect the neuronal apoptosis, supported by histomorphological changes and transmissional electron microscopy (TEM) image. Our data showed that the diabetic rats had a significantly cognitive impairment. In addition to improving glucose metabolism and reducing insulin resistance, berberine significantly improved the cognitive function in the rat. Berberine also effectively decreased the expression of hippocampal tau protein, phosphorylated Tau, and increased insulin receptor antibodies. Moreover, berberine downregulated the abnormal phosphorylation of A[Formula: see text] and Tau protein and improved hippocampal insulin signaling. The TUNEL assay confirmed that berberine reduced hippocampal neuronal apoptosis supported by TEM. Thus, berberine significantly improved the cognitive function in diabetic rats by changing the peripheral and central insulin resistance. The reduction of neuronal injury, A[Formula: see text] deposition, abnormal phosphorylation of Tau protein, and neuronal apoptosis in the hippocampus were observed as the related mechanisms of action.

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Abstract P725: Cerebral Endothelial Cell Derived Exosomes Promote Neurogenesis and Improve Cognitive Function in Aged Diabetic Rats

Stroke ◽

10.1161/str.52.suppl_1.p725 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Li Zhang ◽

Chao Li ◽

Chunyang Wang ◽

Rui Huang ◽

Michael Chopp ◽

...

Keyword(s):

Endothelial Cells ◽

Cognitive Function ◽

Type Ii Diabetes Mellitus ◽

Diabetic Rats ◽

Hippocampal Neurogenesis ◽

Adult Rats ◽

Odor Recognition ◽

Cerebral Endothelial Cells ◽

The Social ◽

Interaction Test

Introduction: Middle age and elderly patients with type II diabetes mellitus (DM) are at high risk to develop cognitive decline and dementia. Reduction of hippocampal neurogenesis is highly associated with impairment of cognitive function. Exosomes are small extracellular vesicles that play an important role in intercelluar communication by transferring proteins, lipids, and genomic materials including microRNAs between cells. In the present study, we tested the hypothesis that exosomes derived from healthy cerebral endothelial cells promote hippocampal neurogenesis and ameliorate cognitive impairment in aged DM rats. Methods: DM was induced in middle aged rats (13 month) by co-administration of nicotinamide and streptozotocin (NTM-STZ). Two months (2M) after NTM-STZ injection, rats with confirmed hyperglycemia were treated with exosomes derived from cerebral endothelial cells of healthy young-adult rats (CEC-Exo, 1x10 11 particles, IV, n=10) or saline (n=10), twice a week for 8 consecutive weeks. Bromodeoxyuridine (BrdU, IP) was administered daily for 7 days starting at 2M after NTM-STZ injection. Results: Compared with DM rats treated with saline, treatment of DM rats with CEC-Exo significantly (p<0.05) improved cognitive functions measured by Morris water maze (47±4% vs 40±5% of time spent in the correct quadrant), odor recognition test (56±6% vs 48±7% time spent on new odor), and the social interaction test (67±9% vs 54±14% interaction time with new rat). In addition, CEC-Exo robustly increased number of BrdU + cells by 60% and DCX + cells by 45% in the subgranular zone of the dentate gyrus compared with saline. Moreover, DCX + cells significantly increased their branch numbers by 54% and lengths by 51% in DM rats treated with CEC-Exo, suggesting that CEC-Exo promote DCX + neuroblasts maturation. Concurrently, CEC-Exo treatment significantly reduced numbers of vessels with fibrin deposition (8±3/mm 2 vs 18±7/mm 2 in saline) and extravascular leakage (3±2/mm 2 vs 7±3/mm 2 in saline) in the hippocampus. Conclusion: Treatment with CEC-Exo improves cognitive function in aged DM rats and augments neurogenesis and reduction of vascular thrombosis in the hippocampus, which in concert likely contribute the therapeutic effect of CEC-Exo.

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