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Recently, astrocytes are fast climbing the ladder of importance in cognitive-related diseases. Perioperative neurocognitive disorder (PND) is a common consequence of anesthesia and surgery, which is widely investigated in elderly and susceptible individuals. There is no doubt that astrocytes also play an irreplaceable role in the pathogenesis of PND. Reactive astrocytes can be found in the PND model, with an altered phenotype and morphology, suggesting a role in the development of the diseases. As a prominent participant cell in the central inflammatory response, the inflammatory response is unavoidably a crucial pathway in the development of the disease. Astrocytes also play a significant role in the homeostasis of the internal environment, neuronal metabolism, and synaptic homeostasis, all of which have an impact on cognitive function. In this article, we discuss the function of astrocytes in PND in order to establish a framework for investigating treatments for PND that target astrocytes.

The inhalation anesthetic isoflurane has been reported to induce caspase activation and apoptosis, which may lead to learning and memory impairment. However, the underlying mechanisms of these effects are largely unknown. Isoflurane has been shown to induce elevation of cytosol calcium levels, accumulation of reactive oxygen species (ROS), opening of the mitochondrial permeability transition pore, reduction in mitochondria membrane potential, and release of cytochrome c. The time course of these effects, however, remains to be determined. Therefore, we performed a pilot study to determine the effects of treatment with isoflurane for various times on ROS levels in HEK-293 cells. The cells were treated with 2% isoflurane plus 21% O2 and 5% CO2 for 15, 30, 60, or 90 min. We then used fluorescence imaging and microplate fluorometer to detect ROS levels. We show that 2% isoflurane for 60 or 90 min, but not 15 or 30 min, induced ROS accumulation in the cells. These data illustrated that isoflurane could cause time-dependent effects on ROS levels. These findings have established a system to further determine the time course effects of isoflurane on cellular and mitochondria function. Ultimately, the studies would elucidate, at least partially, the underlying mechanisms of isoflurane-induced cellular toxicity.