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Hongjam (HJ) is the steamed and freeze-dried powder of larva-stage silkworm (Bombyx mori) rich in protein, unsaturated fatty acids, and minerals. Silkworm products have traditionally been used for medical purposes, and their effectiveness in diabetic and neurodegenerative diseases has been studied. In particular, the anti-inflammatory-antioxidant, blood sugar-lowering, and neuroprotective effects are expected to be useful for the prevention and treatment of dementia, especially in a model of dementia related to insulin resistance. Most animal models of Alzheimer’s disease (AD) are based on genetic factors and research based on these models does not explain the pathophysiology of sporadic AD. Therefore, no drug can effectively delay the progression of AD. We hypothesized that HJ may improve cognitive function in an insulin resistance model which is considered one of the causes of sporadic AD. Insulin resistance was induced by a high-fat diet and streptozotocin injection. Additionally, the effect of HJ was tested in in vitro cultured hippocampal slices treated with an N-methyl-D-aspartate antagonist. At the given dose, HJ did not affect on the body weight but lowered blood glucose concentration, improved spatial memory in the Morris water maze and avoidance memory in the passive avoidance tests which was related to hippocampal brain-derived neurotrophic factor. In hippocampal slices, HJ strengthened long-term potentiation, which was suppressed by AP5. Thus, HJ improved cognitive functions in an insulin-resistance related dementia model and may be useful in treating sporadic AD.Hongjam（HJ）是家蚕（Bombyx mori）幼虫经蒸煮、冻干制备的粉末，富含蛋白质、不饱和脂肪酸与矿物质。蚕制品传统上被应用于医药领域，其在糖尿病与神经退行性疾病中的功效已得到研究。其中抗炎抗氧化、降血糖及神经保护的作用，有望用于痴呆的预防与治疗，尤其是针对胰岛素抵抗相关的痴呆模型。当前绝大多数阿尔茨海默病（Alzheimer’s disease, AD）动物模型均基于遗传因素构建，基于此类模型的研究无法阐释散发性阿尔茨海默病的病理生理学机制，因此目前尚无药物可有效延缓AD的病情进展。本研究假设HJ可改善被认为是散发性AD病因之一的胰岛素抵抗模型的认知功能。实验通过高脂饮食联合链脲佐菌素注射诱导胰岛素抵抗模型。此外，研究还在经N-甲基-D-天冬氨酸（N-methyl-D-aspartate, NMDA）拮抗剂处理的体外培养海马脑片中，测试了HJ的生物学效应。在设定给药剂量下，HJ不会影响受试动物的体重，但可降低血糖浓度，改善莫里斯水迷宫（Morris water maze）检测的空间记忆能力与被动回避实验（passive avoidance tests）中的回避记忆能力，该效应与海马脑源性神经营养因子（brain-derived neurotrophic factor, BDNF）的表达相关。在海马脑片实验中，HJ可增强被AP5抑制的长时程增强（long-term potentiation, LTP）效应。综上，HJ可改善胰岛素抵抗相关痴呆模型的认知功能，有望用于散发性AD的治疗。