Regional and Temporal Profiles of Calpain and Caspase-3 Activities in Postnatal Rat Brain following Repeated Propofol Administration

Abstract

Exposure of newborn rats to a variety of anesthetics has been shown to induce apoptotic neurodegeneration in the developing brain. We investigated the effect of the general anesthetic propofol on the brain of 7-day-old (P7) Wistar rats during the peak of synaptic growth. Caspase and calpain protease families most likely participate in neuronal cell death. Our objective was to examine regional and temporal patterns of caspase-3 and calpain activity following repeated propofol administration (20 mg/kg). P7 rats were exposed for 2, 4 or 6 h to propofol and killed 0, 4, 16 and 24 h after exposure. Relative caspase-3 and calpain activities were estimated by Western blot analysis of the proteolytic cleavage products of α-II-spectrin, protein kinase C and poly(ADP-ribose) polymerase 1. Caspase-3 activity and expression displayed a biphasic pattern of activation. Calpain activity changed in a region- and time-specific manner that was distinct from that observed for caspase-3. The time profile of calpain activity exhibited substrate specificity. Fluoro-Jade B staining revealed an immediate neurodegenerative response that was in direct relationship to the duration of anesthesia in the cortex and inversely related to the duration of anesthesia in the thalamus. At later post-treatment intervals, dead neurons were detected only in the thalamus 24 h following the 6-hour propofol exposure. Strong caspase-3 expression that was detected at 24 h was not followed by cell death after 2- and 4-hour exposures to propofol. These results revealed complex patterns of caspase-3 and calpain activities following prolonged propofol anesthesia and suggest that both are a manifestation of propofol neurotoxicity at a critical developmental stage.

The Fas Ligand/Fas Death Receptor Pathways Contribute to Propofol-Induced Apoptosis and Neuroinflammation in the Brain of Neonatal Rats

“…P7 rat pups (n = 92) were administered either 2, 4, or 6 bolus injections of 20 mg/kg of propofol intraperitoneally at 1 h intervals in order to achieve either 2-, 4-, or 6-h-long anesthesia (Milanovic et al 2010). The animals were decapitated either immediately after cessation of the exposure times (designated as the 0 h time point), or after the recovery periods that lasted 4, 16 or 24 h following termination of propofol exposure (and are referred to as 4, 16, and 24 h time points, respectively).…”

“…Regarding our previous findings about propofol anesthesia duration-and structure-dependent neurodegeneration (Milanovic et al 2010), we opted to test long-term behavioral consequences of 6 h-long propofol exposure. Behavioral experiments were performed between 09:00 and 14:00 h. Animals neonatally exposed to propofol anesthesia (n = 6 per group) and control, saline injected animals (n = 6 per group) were habituated to experimental cages for three consecutive days (intersession activity) starting from age P35 (early adolescence in rats, Laviola et al 2003).…”

“…It is a powerful modulator of neuronal activity by potentiating inhibitory signaling through GABA A receptors and inhibiting excitatory signaling via NMDA receptors (Loepke and Soriano 2008;Alkire et al 2008). The apoptotic cell death, one of the main anesthesiainduced neurotoxic effects observed in experimental studies, has been well documented on histopathological level for almost all common general anesthetics, including propofol (Ikonomidou et al 1999;Jevtovic-Todorovic et al 2003;Pesic et al 2009;Bercker et al 2009;Milanovic et al 2010). Repeated exposure to propofol induces exposure-time-dependent neuronal cell loss and long-term neurocognitive deficits in neonatal rats (Yu et al 2013).…”

“…However, molecular mechanisms of propofol-induced apoptotic cell death are still not completely resolved. We and others have identified an activation of extrinsic apoptotic pathway triggered by increased TNFa expression and deprivation of neurotrophic factors accompanied by p75 receptor upregulation as possible mechanisms of propofol neurotoxicity (Pesic et al 2009;Milanovic et al 2010;Popic et al 2012;Pearn et al 2012;Milanovic et al 2014;Popic et al 2015). However, the potential role of other members of extrinsic apoptotic pathway, like Fas ligand and Fas death receptor cascade, as well as role of intrinsic apoptotic signaling represented by Bcl-2 family gene expression in propofol-mediated cell death has been neglected.…”

<b>Damage caused by exposure to propofol during gestation of mice

“…Health Sciences Maringá, v. 39, n. 2, p. 133-139, July-Dec., 2017 that these receptors were modulated by anesthetics; however, information about the effects of propofol on central neurons is scarce. In addition, propofol causes the death of brain cells in neonatal experimental animal (Vutskits, Gascon, Tassonyi, & Kiss, 2005;Cattano et al, 2008;Pesić et al, 2009;Bercker et al, 2009;Milanovic et al, 2010) and long-term behavioral deficits in the developing brain (Yu, Jiang, Gao, Liu, & Chen, 2013). Another example of propofol toxicity was verified by Cheng et al, (2010) who found that propofol prevented the proliferation of cardiac fibroblasts, by interfering with the generation of reactive oxygen species.…”