The propofol-induced mitochondrial damage in fetal rat hippocampal neurons via the AMPK/P53 signaling pathway

Abstract

Background: Propofol is a commonly used general anesthetic that may cause neuronal damage, especially in infants and young children. Mitochondria play an essential role in cellular metabolism and signal transduction. Propofol may cause neurotoxicity by inhibiting mitochondrial function, but the mechanism by this which occurs remains unclear.Methods: First, the primary rat hippocampal neurons were cultured for 7 days in vitro. The neurons were incubated with propofol at different times or different concentrations, and then the adenosine triphosphate (ATP), reactive oxygen species (ROS), mitochondrial membrane potential, and apoptosis-related proteins were analyzed. Based on the results of the 1st phase, the neurons were then incubated with propofol (100 μM) or corresponding reagents, including 5-aminoimidazole-4-carboxamide ribonucleotide, tenovin-1, and pifithrin-α. Subsequently, the ATP, ROS, mitochondrial membrane potential, phospho-adenosine 5'-monophosphate-activated protein kinase (p-AMPK), protein 53 (p53), and related apoptosis proteins were analyzed.Results: Higher propofol concentrations or longer incubation times were associated with more pronounced decreases in ATP, B-cell lymphoma 2 (Bcl-2), and mitochondrial membrane potential, and more pronounced increases in ROS, BCL2-associated X (Bax), Cytochrome C (CytC), and cleaved caspase-9. Additionally, after incubation with propofol (100 μM), neuronal Bcl-2, p-AMPK, ATP, and mitochondrial membrane potential were downregulated, and ROS, p53, CytC, Bax, cleaved caspase-3, and cleaved caspase-9 were upregulated. AMPK activators or p53 inhibitors reversed the above-mentioned changes.Conclusions: Propofol (100 μM)-induced mitochondrial damage in fetal rat hippocampal neurons may be mediated by the AMPK/p53 signaling pathway. Propofol (100 μM) was shown to inhibit the activity of AMPK in neurons, upregulate the expression of p53, and then activate the mitochondrial-dependent apoptosis pathway, which may lead to neuronal apoptosis.

The effects of general anesthetics on mitochondrial structure and function in the developing brain

“…Subsequent studies have consistently supported the finding of widespread RCD, activated via the intrinsic apoptotic pathway, which includes concurrent elevation of capsase-9, cytochrome C, BAX, and a decrease in anti-apoptotic BCL2, in rat ( 8 , 12 , 63 , 85 , 89 , 114 , 116 , 125 , 134 , 138 – 142 ), mouse ( 62 , 113 , 117 , 143 ) and NHP ( 137 , 144 – 147 ) models, with both in vitro ( 62 , 85 , 113 , 114 , 116 , 139 , 140 ) and in vivo ( 8 , 12 , 62 , 63 , 116 , 117 , 125 , 134 , 138 , 141 – 143 ) experimental protocols. These studies include the use of ISO ( 8 , 116 , 134 , 135 , 138 , 139 , 143 , 144 ), PPF ( 85 , 89 , 114 , 140 ), SEV ( 12 , 62 , 63 , 113 , 117 , 125 , 139 , 141 – 143 ) and KET ( 136 , 137 , 148 ), with varied exposure doses and durations. Ac...…”

“…As the driving force for OXPHOS-derived ATP, MMP is a common indicator for global mitochondrial function and bioenergetic capacity. Depolarization, or loss of MMP, has been ubiquitously observed in rodent models, both in vitro ( 62 , 84 – 89 ) and in vivo ( 13 , 87 , 88 , 90 – 93 ), acutely following exposure to GA-agents including ISO ( 13 , 84 , 86 , 88 ), PPF ( 58 , 85 , 89 ), and SEV ( 62 , 87 , 90 – 93 ) ( Figure 3 ). These observations were also made in conjunction with the measurement of other indicators of OXPHOS dysfunction, such as lower cellular ATP levels [with ISO ( 84 , 88 ), SEV ( 56 , 91 , 92 , 94 ), PPF ( 89 ) and KET ( 56 )] and oxygen consumption rate [with SEV ( 87 , 91 )] indicating reduced bioenergetic capacity of the mitochondria in rodent models.…”

“…Depolarization, or loss of MMP, has been ubiquitously observed in rodent models, both in vitro ( 62 , 84 – 89 ) and in vivo ( 13 , 87 , 88 , 90 – 93 ), acutely following exposure to GA-agents including ISO ( 13 , 84 , 86 , 88 ), PPF ( 58 , 85 , 89 ), and SEV ( 62 , 87 , 90 – 93 ) ( Figure 3 ). These observations were also made in conjunction with the measurement of other indicators of OXPHOS dysfunction, such as lower cellular ATP levels [with ISO ( 84 , 88 ), SEV ( 56 , 91 , 92 , 94 ), PPF ( 89 ) and KET ( 56 )] and oxygen consumption rate [with SEV ( 87 , 91 )] indicating reduced bioenergetic capacity of the mitochondria in rodent models. Long-term energy deficiency has been observed in P300 rats after P7 SEV exposure, as demonstrated by an increase in neuronal ADP/ATP ( 67 ), suggesting that these functional deficits observed acutely can persist.…”

“…These mechanisms may include changes to mitochondrial substrate availability ( 96 ). Similarly, Xiao et al found PPF exposure in primary rat neurons decreased activation of AMP-activated protein kinase (AMPK), an important cellular signal to promote mitochondrial energy production ( 89 ). Metabolic analysis of isolated rat hippocampal tissue sections indicated that SEV or ISO exposure induces a substantial reduction in metabolic demand proportional to the reduction in neuronal activity, but without any alterations to intrinsic mitochondrial complex activity ( 103 ).…”

“…Elevated cellular and mitochondrial ROS accumulations were observed in both in vivo and in vitro developmental rodent models with ISO ( 5 , 13 , 14 , 64 , 86 , 88 ), SEV ( 56 , 66 , 87 , 90 , 93 , 113 ), PPF ( 70 , 85 , 89 , 114 ) and KET ( 56 ) ( Figure 4 ). Common surrogate markers used to measure sustained elevated intracellular oxidative environments in vivo are increased after GA exposure, including depletion of the mitochondrial phospholipid cardiolipin [SEV ( 66 )], increased transcription of oxidative stress-related genes [SEV ( 67 )], the presence of oxidative DNA damage [SEV ( 115 )], and increased lipid peroxidation markers malondioaldehyde (MDA) [SEV ( 9 , 56 , 87 ), ISO ( 13 , 116 ), and KET ( 56 )], 8-isoprostane [ISO ( 14 )] and 4-hydroxynonenal (4HNE) [SEV ( 67 , 117 )].…”