ABSTRACT
ObjectiveSome studies reported that α7nAChR is closely related to the cognitive function. However, the elderly patients have become a high-risk group of postoperative cognitive dysfunction. The aim of this study was to explore the effect of sevoflurane inhalation on the cognitive function and the quantity of alpha 7nicotinic acetycholine receptors in the hippocampus of elderly model rats.MethodsAdult male Sprague-Dawley rats (N=72) were given subcutaneous injection of D-galactose on the neck for 6 weeks to establish elderly models. The model rats were divided into 4 groups randomly: control group (group Con, n=18) with 6h exposure carrier gas (2L/min Air+2L/min O2); Sevoflurane group (group Sev, n=18) with 6 h exposure to 3.2% sevoflurane through carrier gas. Sev+α7nAChR antagonist group (group Sev+M) injected with methyllycaconitine, after 24 h inhaled of 3.2% sevoflurane and carrier gas for 6 h. Sev+α7nAChR agonist group (group Sev+P, n=18) injected with PNU-282987, after 24 h inhaled of 3.2% sevoflurane and carrier gas for 6 h. Morris water maze experiments were conducted on 6 rats in each group 2 h, 1 week and 4 weeks after treatments, respectively. Every cycle after the behavioral test, the hippocampi were taken out. RT-qPCR method was used to detect α7nAChR mRNA expression. Western blotting was used to detect α7nAChR proteins expression.ResultsBehavioral test: compared with Con group at 2 h after awakening, indicators of working memory and spatial probe test in Sev group and Sev+M group decreased significantly (P0.05). RT-qPCR: compared with Con group at 2 h and 1 w after awakening, the expression of alpha 7nAChR mRNA in the other groups was down-regulated, while at 4 w it was up-regulated (P<0.05).Western blot: protein expression of alpha 7nAChR was down-regulated in the 2 h, 1 w Sev group and the Sev+M group after awakening, and up-regulated in the 4 w group after awakening (P<0.05).ConclusionInhalation of 3.2% sevoflurane for 6 h can cause 7nAChR metabolic disturbance in hippocampus of aging model rats and lead to a short-term (1 w) decline in learning and memory ability of the rats, but this effect is reversible. The PNU-282987 agonist can alleviate the temporary decrease of learning and memory caused by sevoflurane.
ABSTRACT
The objective of this study was to evaluate lung protection by the volatile anesthetic sevoflurane (SEVO), which inhibits apoptosis. Male Sprague-Dawley rats (250–280 g; n=18) were randomly divided into three groups. The LPS group received 5 mg/kg endotoxin (lipopolysaccharide), which induced acute lung injury (ALI). The control (CTRL) group received normal saline and the SEVO group received sevoflurane (2.5%) for 30 min after ALI was induced by 5 mg/kg LPS. Samples were collected for analysis 12 h after LPS. Lung injury was assessed by pathological observations and tissue wet to dry weight (W/D) ratios. Apoptotic index (AI) was determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay and electron microscopy. Caspase-3 and cleaved-caspase-3 protein levels were determined by immunocytochemistry and western blotting, respectively. Bcl-xl levels were measured by western blotting and Bcl-2 levels by quantitative real-time polymerase chain reaction and western blotting. In the LPS group, W/D ratios, AI values, caspase-3 and cleaved-caspase-3 levels were significantly higher than in the CTRL group and lung injury was more severe. In the SEVO group, W/D ratios, AI, caspase-3 and cleaved-caspase-3 were lower than in the LPS group. Bcl-2 and Bcl-xl expression were higher than in the LPS group and lung injury was attenuated. Sevoflurane inhalation protected the lungs from injury by regulating caspase-3 activation and Bcl-xl and Bcl-2 expression to inhibit excessive cell apoptosis, and such apoptosis might be important in the pathogenesis of LPS-induced ALI.