Diabetic neuropathy (DN) is an early, common complication of diabetes mellitus (DM) leading to chronic pain, sensory loss and muscle atrophy. Due to its multifactorial etiology, neuron in vitro cultures have been proposed as simplified systems for DN studies. However, the most used models currently available do not recreate the chronic and systemic damage suffered by peripheral neurons of type-2 DM (T2DM) individuals. Here, we cultured neurons derived from dorsal root ganglia from 6-month-old diabetic db/db-mice, and evaluated their morphology by the Sholl method as an easy-to-analyze readout of neuronal function. We showed that neurons obtained from diabetic mice exhibited neuritic regeneration defects in basal culture conditions, compared to neurons from non-diabetic mice. Next, we evaluated the morphological response to common neuritogenic factors including NGF and laminin. Neurons derived from diabetic mice exhibited reduced regenerative responses to these factors compared to neurons from non-diabetic mice. Finally, we analyzed the neuronal response to a putative DN therapy based on the secretome of mesenchymal stem cells (MSC). Neurons from diabetic mice treated with MSC-secretome displayed a significant improvement in neuritic regeneration, but still reduced when compared to neurons derived from non-diabetic mice. This in vitro model recapitulates many alterations observed in sensory neurons of T2DM individuals, suggesting the possibility of studying neuronal functions without the need of adding additional toxic factors to culture plates. This model may be useful for evaluating intrinsic neuronal responses in a cell-autonomous manner, and as a throughput screening for the pre-evaluation of new therapies for DN.

中文翻译：

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源自成年 db/db 小鼠的感觉神经元培养物作为研究 2 型糖尿病相关轴突再生缺陷的简化模型。

糖尿病神经病变 (DN) 是糖尿病 (DM) 的早期常见并发症，可导致慢性疼痛、感觉丧失和肌肉萎缩。由于其多因素病因，体外神经元已提出将培养物作为 DN 研究的简化系统。然而，目前可用的最常用模型无法重现 2 型 DM (T2DM) 个体的外周神经元遭受的慢性和全身性损伤。在这里，我们培养了来自 6 个月大的糖尿病 db/db 小鼠背根神经节的神经元，并通过 Sholl 方法评估了它们的形态，作为一种易于分析的神经元功能读数。我们发现，与非糖尿病小鼠的神经元相比，从糖尿病小鼠获得的神经元在基础培养条件下表现出神经炎再生缺陷。接下来，我们评估了对常见神经发生因子（包括 NGF 和层粘连蛋白）的形态学反应。与来自非糖尿病小鼠的神经元相比，来自糖尿病小鼠的神经元对这些因子的再生反应降低。最后，我们分析了神经元对基于间充质干细胞 (MSC) 分泌组的假定 DN 治疗的反应。来自用 MSC-secretome 治疗的糖尿病小鼠的神经元在神经炎再生方面表现出显着改善，但与来自非糖尿病小鼠的神经元相比，仍然减少。这体外模型概括了在 T2DM 个体的感觉神经元中观察到的许多变化，这表明在不需要向培养板添加额外的毒性因子的情况下研究神经元功能的可能性。该模型可用于以细胞自主方式评估内在神经元反应，并作为对 DN 新疗法的预评估的吞吐量筛选。