Objective: To construct a prediction model for sleep disorders in shift workers of a chemical fiber enterprise, so as to provide the basis for early identification and prevention of sleep disorders in shift workers. Methods: Shift workers were sampled from a chemical fiber enterprise in Tongxiang City, Zhejiang Province using a cluster sampling method from August 2022 to July 2024. Demographic information, length of service and average weekly working hours were collected through questionnaire surveys. Depressive symptoms, anxiety symptoms and sleep disorders were evaluated using the Pittsburgh Sleep Quality Index, Patient Health Questionnaire and Generalized Anxiety Disorder Questionnaire, respectively. The shift workers were randomly divided into a training set and a validation set at a ratio of 7∶3. Predictive factors were selected using a multivariable logistic regression model based on the training set, and a nomograph model for prediction of sleep disorders in shift workers was established. The predictive values of the model were evaluated using the receiver operating characteristic (ROC) curve and calibration curve based on the training set and validation set. Results: Totally 673 shift workers were included, with a median age of 32 (interquartile range, 12) years. There were 493 males, accounting for 73.25%. There were 471 (69.99%) workers in the training set and 202 (30.01%) workers in the validation set. There were 274 workers with sleep disorders, accounting for 40.71%. The equation for the prediction model was ln[p/(1-p)]=-8.391+1.906×average weekly working hours+1.822×depressive symptoms+1.667×anxiety symptoms. The area under the ROC curve was 0.769 (95%CI: 0.661-0.835) for the training set and 0.655 (95%CI: 0.593-0.737) for the validation set, and Hosmer-Lemeshow test showed a good fitting effect (both P>0.05). Conclusion The nomograph model constructed by average weekly working hours, depressive symptoms and anxiety symptoms can be used to predict the risk of sleep disorders in shift workers of a chemical fiber enterprise.

Objective:To evaluate the role of tubulin tyrosin ligase like-6 (TTLL6)-mediated microtubule polyglutamylation and Spastin(a microtubule cleaving protein)-induced excessive microtubule cleavage in the developmental impairment of dendritic spines in neonatal mice following repeated sevoflurane anesthesia, by utilizing TTLL6 conditional knockout mice.Methods:Fifty SPF female TTLL6 brain tissue-specific knockout (TTLL6 CKO: Camk2-Cre + ; TTLL6 f/f) and fifty control (TTLL6 CON: TTLL6 f/f) mice with C57BL/6J background, aged 6 days old were selected.TTLL6 CKO mice were divided into TTLL6 CON control group and TTLL6 CON sevoflurane group, and TTLL6 CKO mice were divided into TTLL6 CKO control group and TTLL6 CKO sevoflurane group, with 25 mice in each group by random block method.Mice in the sevoflurane groups were exposed to 3% sevoflurane with 60% O 2 for 2 hours daily on postnatal days 6, 8, and 10.The mice in control groups received only 60% O 2 under the same condition.The polyGlu-Tubulin and postsynaptic density 95(PSD95) protein expression were detected using Western blot. The expressions of TTLL6, Spastin, and α-Tubulin were assessed via immunofluorescence.Golgi staining and electron microscopy were employed to observe the density of hippocampal dendritic spines and synaptic conditions. The Morris water maze test was used to evaluate spatial memory capabilities. Statistical analysis was performed using GraphPad Prism 8.0 software. Results:(1) Behavioral results showed significant time and group interactions among the four groups in terms of latency to find the platform ( F=8.22, P<0.001).Mice in the TTLL6 CON sevoflurane group had a significantly longer escape latency on days 3-7 compared with the TTLL6 CON control group (all P<0.05), while there was no significant difference between the TTLL6 CKO sevoflurane group and the TTLL6 CKO control group (all P>0.05). The number of platform crossings differed significantly among the four groups ( H=11.95, P=0.007).The TTLL6 CON sevoflurane group had significantly fewer crossing times than the TTLL6 CON control group ( P<0.05), but no significant difference was observed between the TTLL6 CKO sevoflurane group and the TTLL6 CKO control group ( P>0.05). (2) Golgi staining and electron microscopy results revealed significant differences in dendritic spine density and synapse number among the four groups( F=29.00, 41.94, both P<0.001). The dendritic spine density ((5.83±0.40)/10 μm) and the number of synapses ((3.67±0.58)/10 μm) in the TTLL6 CON sevoflurane group were both significantly lower than those in the TTLL6 CON control group ((12.87±1.70)/10 μm, (9.33±0.57)/10 μm)(both P<0.05). In contrast, there was no statistically significant difference between the TTLL6 CKO sevoflurane group and TTLL6 CKO control group (both P>0.05). (3) Immunofluorescence results showed significant differences in the percentage of TTLL6 and Spastin and α-Tubulin co-expressed positive cells in the CA3 region of the hippocampus among the four groups of mice ( F=215.20, 26.08, both P<0.001). The percentage of TTLL6 and Spastin and α-Tubulin co-expressed positive cells in the TTLL6 CON sevoflurane group ((16.75±1.81) %, (47.98±8.42) %) were significantly higher than those in the TTLL6 CON control group ((2.44±0.58) %, (20.07±4.54) %)(both P<0.05), while there was no statistically significant difference between the TTLL6 CKO sevoflurane group and TTLL6 CKO control group ( P>0.05). (4) Western blot results indicated significant differences in the expression of polyGlu-Tubulin and PSD95 proteins in the hippocampal tissue among the four groups of mice ( F=19.66, 8.57, both P<0.001). The TTLL6 CON sevoflurane group had higher polyGlu-Tubulin expression (0.86±0.19) and lower PSD95 expression (0.61±0.13) compared to the TTLL6 CON control group (0.51±0.11, 1.01±0.07) (both P<0.05).However, there was no significant difference between the TTLL6 CKO sevoflurane group and the TTLL6 CKO control group ( P>0.05). Conclusion:The mechanism underlying long-term cognitive impairment in developing brain of neonatal mice caused by repeated sevoflurane anesthesia may relate to the upregulation of TTLL6-induced microtubule polyglutamylation and accelerated Spastin-mediated microtubule severing, which ultimately leads to abnormal dendritic spine development.

Objective:To evaluate the role of tubulin tyrosin ligase like-6 (TTLL6)-mediated microtubule polyglutamylation and Spastin(a microtubule cleaving protein)-induced excessive microtubule cleavage in the developmental impairment of dendritic spines in neonatal mice following repeated sevoflurane anesthesia, by utilizing TTLL6 conditional knockout mice.Methods:Fifty SPF female TTLL6 brain tissue-specific knockout (TTLL6 CKO: Camk2-Cre + ; TTLL6 f/f) and fifty control (TTLL6 CON: TTLL6 f/f) mice with C57BL/6J background, aged 6 days old were selected.TTLL6 CKO mice were divided into TTLL6 CON control group and TTLL6 CON sevoflurane group, and TTLL6 CKO mice were divided into TTLL6 CKO control group and TTLL6 CKO sevoflurane group, with 25 mice in each group by random block method.Mice in the sevoflurane groups were exposed to 3% sevoflurane with 60% O 2 for 2 hours daily on postnatal days 6, 8, and 10.The mice in control groups received only 60% O 2 under the same condition.The polyGlu-Tubulin and postsynaptic density 95(PSD95) protein expression were detected using Western blot. The expressions of TTLL6, Spastin, and α-Tubulin were assessed via immunofluorescence.Golgi staining and electron microscopy were employed to observe the density of hippocampal dendritic spines and synaptic conditions. The Morris water maze test was used to evaluate spatial memory capabilities. Statistical analysis was performed using GraphPad Prism 8.0 software. Results:(1) Behavioral results showed significant time and group interactions among the four groups in terms of latency to find the platform ( F=8.22, P<0.001).Mice in the TTLL6 CON sevoflurane group had a significantly longer escape latency on days 3-7 compared with the TTLL6 CON control group (all P<0.05), while there was no significant difference between the TTLL6 CKO sevoflurane group and the TTLL6 CKO control group (all P>0.05). The number of platform crossings differed significantly among the four groups ( H=11.95, P=0.007).The TTLL6 CON sevoflurane group had significantly fewer crossing times than the TTLL6 CON control group ( P<0.05), but no significant difference was observed between the TTLL6 CKO sevoflurane group and the TTLL6 CKO control group ( P>0.05). (2) Golgi staining and electron microscopy results revealed significant differences in dendritic spine density and synapse number among the four groups( F=29.00, 41.94, both P<0.001). The dendritic spine density ((5.83±0.40)/10 μm) and the number of synapses ((3.67±0.58)/10 μm) in the TTLL6 CON sevoflurane group were both significantly lower than those in the TTLL6 CON control group ((12.87±1.70)/10 μm, (9.33±0.57)/10 μm)(both P<0.05). In contrast, there was no statistically significant difference between the TTLL6 CKO sevoflurane group and TTLL6 CKO control group (both P>0.05). (3) Immunofluorescence results showed significant differences in the percentage of TTLL6 and Spastin and α-Tubulin co-expressed positive cells in the CA3 region of the hippocampus among the four groups of mice ( F=215.20, 26.08, both P<0.001). The percentage of TTLL6 and Spastin and α-Tubulin co-expressed positive cells in the TTLL6 CON sevoflurane group ((16.75±1.81) %, (47.98±8.42) %) were significantly higher than those in the TTLL6 CON control group ((2.44±0.58) %, (20.07±4.54) %)(both P<0.05), while there was no statistically significant difference between the TTLL6 CKO sevoflurane group and TTLL6 CKO control group ( P>0.05). (4) Western blot results indicated significant differences in the expression of polyGlu-Tubulin and PSD95 proteins in the hippocampal tissue among the four groups of mice ( F=19.66, 8.57, both P<0.001). The TTLL6 CON sevoflurane group had higher polyGlu-Tubulin expression (0.86±0.19) and lower PSD95 expression (0.61±0.13) compared to the TTLL6 CON control group (0.51±0.11, 1.01±0.07) (both P<0.05).However, there was no significant difference between the TTLL6 CKO sevoflurane group and the TTLL6 CKO control group ( P>0.05). Conclusion:The mechanism underlying long-term cognitive impairment in developing brain of neonatal mice caused by repeated sevoflurane anesthesia may relate to the upregulation of TTLL6-induced microtubule polyglutamylation and accelerated Spastin-mediated microtubule severing, which ultimately leads to abnormal dendritic spine development.

Objective:To evaluate the effect of sleep fragmentation on postoperative cognitive dysfunction (POCD) and hippocampal glutaminergic metabolism in aged mice anesthetized with isoflurane.Methods:Forty healthy SPF-grade male C57BL/6J mice, aged 18 months, weighing 20-30 g, were divided into 4 groups ( n= 10 each) by the random number table method: normal control group (group C), sleep fragmentation group (group SF), isoflurane anesthesia/surgery group (group I/S), and sleep fragmentation plus isoflurane anesthesia/surgery group (group SF+ I/S). Group C did not received any treatment. Group SF received sleep fragmentation for 24 h. The right carotid artery exposure was performed under isoflurane anesthesia in group I/S. Group SF+ I/S received isoflurane anesthesia/right carotid artery exposure at 24 h after sleep fragmentation. The metabolic levels of glutamate (Glu), glutamine (Gln), Glu/Gln complex (Glx), and N-acetylaspartate (NAA) and their ratio to creatine (Cr) were measured by in vivo 9.4T hydrogen proton magnetic resonance spectroscopy at 2 h after anaesthesia. Y maze and Morris water maze tests were used to evaluate the cognitive function at 1-7 days after surgery. The mice were sacrificed after the behavioral testing, brain tissues were immediately obtained, and the number of Nissl bodies and density of dendritic spines in the hippocampal CA1 region were measured by Nissl staining and Golgi staining, respectively. Results:Compared with group C, the percentage of exploration time and shuttle times at the novel arm were significantly decreased, the number of crossing the original platform was decreased, the time of stay at the target quadrant was shortened, the ratios of Glu/Cr, Gln/Cr and Glx/Cr in the hippocampal CA1 region were increased, and the ratio of NAA/Cr was decreased, and the number of Nissl bodies and density of dendritic spines were decreased in SF, I/S and SF+ I/S groups ( P<0.05). Compared with group SF and group I/S, the percentage of exploration time and shuttle times at the novel arm were significantly decreased, the number of crossing the original platform was decreased, the time of stay at the target quadrant was shortened, the ratios of Glu/Cr and Glx/Cr in hippocampal CA1 region was increased, the ratio of NAA/Cr was decreased, and the number of Nissl bodies and density of dendritic spines were decreased in group SF+ I/S ( P<0.05). Conclusions:Sleep fragmentation exacerbates POCD in aged mice anesthetized with isoflurane, and the mechanism is related to nerve injury induced by abnormality in hippocampal glutaminergic metabolism excitability.