Objective:To evaluate the relationship between the mechanism of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) preventing sevoflurane-induced neurotoxicity and phosphorylated Tau glymphatic system clearance pathway in neonatal mice.Methods:Eighteen C57BL/6 pregnant mice were used in this study and subjected to 2 feeding regiments using the random number table method. Twelve mice were selected to receive a standard diet, and 6 mice were selected to receive a diet supplemented with fish oil (ω-3 polyunsaturated fatty acids [300 mg was added to every 20 g of standard diet from the 2nd day of gestation to 14 days after parturition). The healthy neonatal mice of both sexes, aged 6 days, weighing 3-5 g, were selected after parturition. Forty-eight neonatal pups from 6 pregnant mice that were fed a standard diet were assigned to control group (C group), 48 neonatal pups from 6 pregnant mice that were fed a standard diet were assigned to sevoflurane group (S group), and 48 neonatal pups from pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS group) using the random number table method. All the offspring mice in all groups were breastfed until 21 days of birth and then were housed in separate cages from their mothers after 21 days of birth and provided with ad libitum access to standard food. S group and PS group inhaled 3% sevoflurane and 40% oxygen for 2 h daily on postnatal days 6, 7 and 8. C group inhaled only 40% oxygen at the same flow rate. Y maze test was performed at postnatal day 33 to assess the spatial memory and cognitive function. The rotarod test was performed at postnatal day 35 to assess the fine motor coordination. The influx and efflux functions of the glymphatic system were assessed through intracisternal tracer infusion with the fluorescent tracer at postnatal days 14 and 35. The influx function was evaluated by the percentage of the area of tracer penetration 30 min after injection, while the efflux function was determined by the percentage of the residual area of the tracer 90 min after injection. The mice were sacrificed and the hippocampal tissue was obtained at postnatal day 14 for determination of the expression of phosphorylated Tau protein at serine 202 site and threonine 205 site (Tau-PS202/PT205) and total Tau protein by Western blot. The cerebrospinal fluid (CSF) was collected at postnatal day 14 for determination of the concentration of phosphorylated Tau protein by enzyme-linked immunosorbent assay. The mice were sacrificed and the hippocampal tissue was obtained at postnatal day 35 for determination of the expression of caspase-3, caspase-9 and cytochrome C (Cyt c) (by Western blot) and the apoptosis rate of neurons (by TUNEL).Results:Compared with C group, the time of staying at the new arm and in the rotarod test was significantly shortened, the percentage of new arm movement distance was decreased, the percentage of tracer penetration area was decreased at postnatal day 14, the percentage of residual tracer area was increased at postnatal day 14, the expression of Tau-PS202/PT205 in the hippocampus was up-regulated at postnatal day 14, the concentration of phosphorylated Tau protein in CSF was reduced at postnatal day 14, the apoptosis rate of hippocampal neurons was increased at postnatal day 35 ( P<0.05), and the expression of caspase-3, caspase-9 and Cyt c in the hippocampus was up-regulated at postnatal day 35 in S group ( P<0.05). Compared with S group, the time of staying at the new arm and in the rotarod test was significantly prolonged, the percentage of new arm movement distance was increased, the percentage of tracer penetration area was increased at postnatal day 14, the percentage of residual tracer area was decreased at postnatal day 14, the expression of Tau-PS202/PT205 in the hippocampus was down-regulated at postnatal day 14, the concentration of phosphorylated Tau protein in CSF was increased at postnatal day 14, the apoptosis rate of hippocampal neurons was decreased at postnatal day 35, and the expression of caspase-3, caspase-9 and Cyt c in the hippocampus was down-regulated at postnatal day 35 in PS group ( P<0.05). Conclusions:The mechanism by which ω-3 PUFAs prevents cerebral neurotoxicity induced by repeated neonatal sevofurane exposure may be related to the enhancement of phosphorylated Tau protein clearance via the glymphatic system.

Objective:To evaluate the relationship between the mechanism of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) in preventing brain neurotoxicity caused by multiple sevoflurane anesthesia and peroxisome proliferator-activated receptor gamma (PPARγ)/peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) signaling pathway in neonatal mice.Methods:This study was performed in 2 parts. Part Ⅰ Using a random number table method, 6 C57BL/6 pregnant mice were assigned to receive a standard diet, 3 pregnant mice were assigned to receive a diet supplemented with fish oil from day 2 of gestation to day 14 after parturition (ω-3 PUFAs 300 mg were added to every 20 g of conventional diet). Healthy C57BL/6 mice of both sexes, aged 6 days, weighing 3-5 g, were selected after parturition. Seventeen neonatal pups from 3 pregnant mice that were fed a conventional diet were assigned to control group (C group), 17 neonatal pups from 3 pregnant mice that were fed a conventional diet were assigned to sevoflurane group (S group), and 17 neonatal pups from pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS1 group) using the random number table method. Part Ⅱ Four C57BL/6 pregnant mice were assigned to receive a diet supplemented with fish oil from day 2 of gestation to day 14 after parturition. After parturition, 12 neonatal pups from 2 pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS2 group), and 12 neonatal pups from 2 pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus PPARγ inhibitor GW9662 plus sevoflurane group (PGS group) using a random number table method. GW9662 (2 mg/kg) was intraperitoneally injected at 30 min before exposure to sevoflurane in PGS group. All offspring mice were breastfed until 21 days of age, after which they were housed separately from the mother and allowed ad libitum access to a conventional diet. S, PS1, PS2 and PGS groups inhaled 3% sevoflurane in 40% oxygen for 2 h daily on postnatal days 6, 7 and 8. C group inhaled only 40% oxygen instead. Y maze test was performed on days 33 after birth. The rotarod test was performed on day 35 after birth. After the behavioral testing, the expression of PPARγ, PGC1α, mitofusin-1 (MFN1), MFN2, dynamin-related protein 1 (DRP1), interleukin-6 (IL-6), interleukin-1 β (IL-1 β), and tumor necrosis factor-α (TNF-α) was detected by Western blot, the ultrastructure of mitochondria in hippocampal neurons was observed with a transmission electron microscope, and the mitochondrial membrane potential (MMP), level of reactive oxygen species (ROS) and content of ATP were determined.Results:Part Ⅰ Compared with C group, the time of stay at the new-arm and time spent on the rotarod were significantly shortened, the percentage of movement distance in the new-arm was decreased, the expression of PPARγ, PGC1α, MFN1 and MFN2 in the hippocampus was down-regulated, the expression of DRP1, IL-6, IL-1β and TNF-α in the hippocampus was up-regulated, the MMP and content of ATP were decreased, and the level of ROS was increased in S group ( P<0.05). Compared with S group, the time of stay at the new-arm and time spent on the rotarod were significantly prolonged, the percentage of movement distance in the new-arm was increased, the expression of PPARγ, PGC1α, MFN1 and MFN2 in the hippocampus was up-regulated, the expression of DRP1, IL-6, IL-1β and TNF-α in the hippocampus was down-regulated, the MMP and content of ATP were increased, and the level of ROS was decreased in PS1 group ( P<0.05). Part Ⅱ Compared with PS2 group, the time of stay at the new-arm and time spent on the rotarod were significantly shortened, the percentage of movement distance in the new-arm was decreased, the MMP and content of ATP were decreased, the level of ROS was increased, and the expression of IL-6, IL-1β and TNF-α was up-regulated ( P<0.05). Conclusions:The mechanism by which ω-3 PUFAs prevent brain neurotoxicity caused by multiple sevoflurane anesthesia is related to the activation of the PPARγ/PGC1α signaling pathway and alleviation of mitochondrial dysfunction and neuroinflammation in neonatal mice.

Objective:To evaluate the relationship between the mechanism of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) preventing sevoflurane-induced neurotoxicity and phosphorylated Tau glymphatic system clearance pathway in neonatal mice.Methods:Eighteen C57BL/6 pregnant mice were used in this study and subjected to 2 feeding regiments using the random number table method. Twelve mice were selected to receive a standard diet, and 6 mice were selected to receive a diet supplemented with fish oil (ω-3 polyunsaturated fatty acids [300 mg was added to every 20 g of standard diet from the 2nd day of gestation to 14 days after parturition). The healthy neonatal mice of both sexes, aged 6 days, weighing 3-5 g, were selected after parturition. Forty-eight neonatal pups from 6 pregnant mice that were fed a standard diet were assigned to control group (C group), 48 neonatal pups from 6 pregnant mice that were fed a standard diet were assigned to sevoflurane group (S group), and 48 neonatal pups from pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS group) using the random number table method. All the offspring mice in all groups were breastfed until 21 days of birth and then were housed in separate cages from their mothers after 21 days of birth and provided with ad libitum access to standard food. S group and PS group inhaled 3% sevoflurane and 40% oxygen for 2 h daily on postnatal days 6, 7 and 8. C group inhaled only 40% oxygen at the same flow rate. Y maze test was performed at postnatal day 33 to assess the spatial memory and cognitive function. The rotarod test was performed at postnatal day 35 to assess the fine motor coordination. The influx and efflux functions of the glymphatic system were assessed through intracisternal tracer infusion with the fluorescent tracer at postnatal days 14 and 35. The influx function was evaluated by the percentage of the area of tracer penetration 30 min after injection, while the efflux function was determined by the percentage of the residual area of the tracer 90 min after injection. The mice were sacrificed and the hippocampal tissue was obtained at postnatal day 14 for determination of the expression of phosphorylated Tau protein at serine 202 site and threonine 205 site (Tau-PS202/PT205) and total Tau protein by Western blot. The cerebrospinal fluid (CSF) was collected at postnatal day 14 for determination of the concentration of phosphorylated Tau protein by enzyme-linked immunosorbent assay. The mice were sacrificed and the hippocampal tissue was obtained at postnatal day 35 for determination of the expression of caspase-3, caspase-9 and cytochrome C (Cyt c) (by Western blot) and the apoptosis rate of neurons (by TUNEL).Results:Compared with C group, the time of staying at the new arm and in the rotarod test was significantly shortened, the percentage of new arm movement distance was decreased, the percentage of tracer penetration area was decreased at postnatal day 14, the percentage of residual tracer area was increased at postnatal day 14, the expression of Tau-PS202/PT205 in the hippocampus was up-regulated at postnatal day 14, the concentration of phosphorylated Tau protein in CSF was reduced at postnatal day 14, the apoptosis rate of hippocampal neurons was increased at postnatal day 35 ( P<0.05), and the expression of caspase-3, caspase-9 and Cyt c in the hippocampus was up-regulated at postnatal day 35 in S group ( P<0.05). Compared with S group, the time of staying at the new arm and in the rotarod test was significantly prolonged, the percentage of new arm movement distance was increased, the percentage of tracer penetration area was increased at postnatal day 14, the percentage of residual tracer area was decreased at postnatal day 14, the expression of Tau-PS202/PT205 in the hippocampus was down-regulated at postnatal day 14, the concentration of phosphorylated Tau protein in CSF was increased at postnatal day 14, the apoptosis rate of hippocampal neurons was decreased at postnatal day 35, and the expression of caspase-3, caspase-9 and Cyt c in the hippocampus was down-regulated at postnatal day 35 in PS group ( P<0.05). Conclusions:The mechanism by which ω-3 PUFAs prevents cerebral neurotoxicity induced by repeated neonatal sevofurane exposure may be related to the enhancement of phosphorylated Tau protein clearance via the glymphatic system.

Objective:To evaluate the relationship between the mechanism of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) in preventing brain neurotoxicity caused by multiple sevoflurane anesthesia and peroxisome proliferator-activated receptor gamma (PPARγ)/peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) signaling pathway in neonatal mice.Methods:This study was performed in 2 parts. Part Ⅰ Using a random number table method, 6 C57BL/6 pregnant mice were assigned to receive a standard diet, 3 pregnant mice were assigned to receive a diet supplemented with fish oil from day 2 of gestation to day 14 after parturition (ω-3 PUFAs 300 mg were added to every 20 g of conventional diet). Healthy C57BL/6 mice of both sexes, aged 6 days, weighing 3-5 g, were selected after parturition. Seventeen neonatal pups from 3 pregnant mice that were fed a conventional diet were assigned to control group (C group), 17 neonatal pups from 3 pregnant mice that were fed a conventional diet were assigned to sevoflurane group (S group), and 17 neonatal pups from pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS1 group) using the random number table method. Part Ⅱ Four C57BL/6 pregnant mice were assigned to receive a diet supplemented with fish oil from day 2 of gestation to day 14 after parturition. After parturition, 12 neonatal pups from 2 pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus sevoflurane group (PS2 group), and 12 neonatal pups from 2 pregnant mice that were fed a diet supplemented with fish oil were assigned to ω-3 PUFAs plus PPARγ inhibitor GW9662 plus sevoflurane group (PGS group) using a random number table method. GW9662 (2 mg/kg) was intraperitoneally injected at 30 min before exposure to sevoflurane in PGS group. All offspring mice were breastfed until 21 days of age, after which they were housed separately from the mother and allowed ad libitum access to a conventional diet. S, PS1, PS2 and PGS groups inhaled 3% sevoflurane in 40% oxygen for 2 h daily on postnatal days 6, 7 and 8. C group inhaled only 40% oxygen instead. Y maze test was performed on days 33 after birth. The rotarod test was performed on day 35 after birth. After the behavioral testing, the expression of PPARγ, PGC1α, mitofusin-1 (MFN1), MFN2, dynamin-related protein 1 (DRP1), interleukin-6 (IL-6), interleukin-1 β (IL-1 β), and tumor necrosis factor-α (TNF-α) was detected by Western blot, the ultrastructure of mitochondria in hippocampal neurons was observed with a transmission electron microscope, and the mitochondrial membrane potential (MMP), level of reactive oxygen species (ROS) and content of ATP were determined.Results:Part Ⅰ Compared with C group, the time of stay at the new-arm and time spent on the rotarod were significantly shortened, the percentage of movement distance in the new-arm was decreased, the expression of PPARγ, PGC1α, MFN1 and MFN2 in the hippocampus was down-regulated, the expression of DRP1, IL-6, IL-1β and TNF-α in the hippocampus was up-regulated, the MMP and content of ATP were decreased, and the level of ROS was increased in S group ( P<0.05). Compared with S group, the time of stay at the new-arm and time spent on the rotarod were significantly prolonged, the percentage of movement distance in the new-arm was increased, the expression of PPARγ, PGC1α, MFN1 and MFN2 in the hippocampus was up-regulated, the expression of DRP1, IL-6, IL-1β and TNF-α in the hippocampus was down-regulated, the MMP and content of ATP were increased, and the level of ROS was decreased in PS1 group ( P<0.05). Part Ⅱ Compared with PS2 group, the time of stay at the new-arm and time spent on the rotarod were significantly shortened, the percentage of movement distance in the new-arm was decreased, the MMP and content of ATP were decreased, the level of ROS was increased, and the expression of IL-6, IL-1β and TNF-α was up-regulated ( P<0.05). Conclusions:The mechanism by which ω-3 PUFAs prevent brain neurotoxicity caused by multiple sevoflurane anesthesia is related to the activation of the PPARγ/PGC1α signaling pathway and alleviation of mitochondrial dysfunction and neuroinflammation in neonatal mice.