Ntethelelo Sibiya and Musa Mabandla
Background: Diabetics are at high risk of developing dementia associated diseases compared to non-diabetics. The learning and memory impairments manifested in diabetes are attributed to sustained hyperglycemia. Insulin injections are beneficial in preventing and attenuating the progression of these impairments. However, undesirable effects associated with the current mode of administration remains a challenge. In this study, we evaluated the effects of pectin-insulin patch on learning and memory deficits in diabetic animals.
Methods: Pectin-insulin patches (20.0, 40.8 and 82.9 μg/kg) applied on the skin of streptozotocin-induced diabetic rats, thrice daily for 45 days. Learning and memory was assessed using the Morris water maze and the novel object recognition behavioural paradigms. Blood glucose, hippocampal mass, hippocampal insulin receptor, tumour necrosis factor (TNFα) and C reactive protein (CRP) concentrations were examined.
Results: Patch treatments attenuated diabetes induced hyperglycaemia. The diabetic controls showed significant deficits in learning, spatial and recognition memory. The application of the patch attenuated the learning, spatial and recognition deficits observed in diabetic controls. Diabetic animals presented with up-regulated hippocampal insulin receptor which was not affected by the patch treatment. Patch treatments abolished diabetes induced increases in hippocampal TNF α and CRP concentration.
Conclusions: The pectin-insulin patch improves learning and memory and attenuates hippocampal TNFα and CRP in streptozotocin-induced diabetic rats. These observations may suggest that pectin-insulin patches may present an alternative chronic treatment mode for diabetes considering the challenges associated with insulin injections.