Palmitate treated-astrocyte conditioned medium contains increased glutathione and interferes in hypothalamic synaptic network in vitro

Abstract

Excessive fat consumption increases the level of fatty acids (FAs) in the blood, which reach the hypothalamus and damage the circuit related to energy balance. In the present study, we used palmitate in a primary culture of purified astrocytes to mimic the fat-rich environment found in obesity. Our results showed increased glial fibrillary acidic protein (GFAP) reactivity in hypothalamic astrocytes compared to cortical astrocytes. In addition, palmitate-treated astrocytes showed no significant changes in cytokine expression and an upregulation of glutathione in the culture medium that may serve as an intrinsic neuroprotective property against excess FA. Additionally, purified hypothalamic neurons were incubated with palmitate-treated astrocyte-conditioned medium (MPAL). MPAL treated-neurons exhibited a reduction in excitatory synapses and enhanced neuritogenesis. Our results suggest that hypothalamic astrocytes react to palmitate differently than cortical astrocytes and influence the behavior of the neural network related to energy balance. Our work brings a better understanding of the interactions among hypothalamic neurons in a high FA environment, similarly to obesity induced by a high-fat diet.

Keywords: Astrocyte; Fatty acid; Glutathione; Hypothalamus; Palmitate; Synapse.