Sensory neuron cultures derived from adult db/db mice as a simplified model to study type-2 diabetes-associated axonal regeneration defects

Diabetic neuropathy (DN) is an early common complication of diabetes mellitus (DM), leading to chronic pain, sensory loss and muscle atrophy. Owing to its multifactorial etiology, neuron in vit,o cultures hav e 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 nonoiabetic mice. Next, we evaluated the morphological response to common neuritogenic factors, including nerv e growth factor NGF and Laminin-1 (also called Laminin-111). Neurons derived from diabetic mice exhibited reduced regenerativ e responses to these factors compared to neurons from nonoiabetic mice. Finally, we analyzed the neuronal response to a putativ e DN therapy based on the secretome of mesenchymal stem cells (MSC). Neurons from diabetic mice treated with the MSC secretome displayed a significant improvement in neuritic regeneration, but still reduced when compared to neurons derived from nonoiabetic mice. This in vit,o 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.

Automated summary

Diabetic neuropathy (DN) is a common complication of diabetes mellitus (DM) leading to chronic pain, sensory loss, and muscle atrophy. Neurons derived from diabetic mice exhibit regeneration defects and reduced responses to neurotrophic factors compared to non-diabetic mice. Treatment with mesenchymal stem cell secretome improves neuritic regeneration in diabetic neurons but remains reduced compared to non-diabetic neurons.