Spatiotemporal variation and source analysis of air pollutants in the Harbin-Changchun (HC) region of China during 2014-2020

This study analyzed the characteristics of air pollution and specific pollution periods within the Harbin-Changchun (HC) metropolitan area during 2014-2020. Regarding annual, seasonal, and monthly variations of the six pollutants, the change trend in 11 cities of HC showed strong consistency in spatial distribution. The western cities (Songyuan, Daqing, and Siping) were vulnerable to dust storms from Inner Mongolia. The concentrations of all air pollutants, except O₃-8h, showed downward fluctuation trends from 2014 to 2018 and remained stable from 2018 to 2020 in terms of annual variations. The inter-annual trend of significant reductions in SO₂ and SO₂/PM_2.5 during the heating period indicated that strict emission reduction measures posed by the government were highly successful. The ratio of PM_2.5/SO₂ was used to identify open biomass burning (OBB), which showed a double peak (October-November (Oct-Nov), March-April (Mar-Apr)). The burning prohibition shifted the OBB from Oct-Nov to Mar-Apr.

[Clinical and prognosis analysis of children with kidney retransplantation]

Objective: To analyze the clinical and prognosis of children with kidney retransplantation. Methods: Clinical data of 11 children who underwent kidney retransplantation from January 2011 to December 2020 in Department of Nephrology, Children's Hospital of Fudan University were retrospectilely analyzed. The clinical data including demographic parameters, primary diagnosis, characteristics in the follow-up of renal allograft were analyzed. Results: Totally 11 cases received secondary renal transplantation (male 6, female 5). They were initially diagnosed with chronic kidney disease at the age of 11.9 (7.4, 13.3) years. The median duration of dialysis was 22.1 (3.5, 36.5) months. In the first transplantation, recipient age was 13.9 (11.1, 15.2) years. Ten cases received donation from cardiac death donor (DCD) (9 cases received donors aged less than one year, 5 of them received whole kidney transplantation and one case received donor aged one to three years) and 1 case with living-related donor. Ten graft failures occurred within 1 month after renal transplantation and the other one occurred at the fifth month after transplantation. The causes included vascular factors (9 cases), rejection (1 case) and primary non-function (1 case). In the second transplantation, recipient age was 14.7 (11.7, 16.2) years. All the 11 children received dialysis (7 with PD and 4 with HD) and successfully completed the second transplantation. The median time between the two transplants was 210 (16, 1 041) days. Donors were all DCD donors from 3 years of age or older. The mean follow-up duration was (42±15) months. The estimated glomerular filtration rate was (85±34)ml/(min·1.73 m²) when the last investigation after kidney retransplantation with the kidney and patient all survived. Conclusions: Kidney retransplantation may have better prognosis in children. Dialysis transition during waiting period and DCD donor from 3 years of age or older can effectively ensure the success of kidney retransplantation.

Construction of Aptamer-Based Molecular Beacons with Varied Blocked Structures and Targeted Detection of Thrombin

A kind of blocked aptamer-functionalized molecular beacon (MB) was designed as fluorescence sensors to detect thrombins by binding-induced "turn on" structural transformation. Three MBs named MB(8 + 8), MB(15 + 8), and MB(15 + 6) consisted of two single-stranded oligonucleotides. One long single-stranded oligonucleotide (abbreviated as SS) contained a thrombin aptamer sequence and was modified with a fluorescence group and quenching group on each end side. Another short single-stranded oligonucleotide (written as cDNA) was partially complementary to the long SS. It was interesting to find that the complementary sequence length of cDNA greatly influenced the structure of the MBs. The construction of MB experiments proved that MB(8 + 8) and MB(15 + 8) could form the quenching MBs but MB(15 + 6) could not. MB(8 + 8) was composed of a SS strand paired with a complementary cDNA(8 + 8), which was called one-to-one combination, while MB(15 + 8) was two-to-two combination and MB(15 + 6) was one-to-two combination. When the ratio of SS and cDNA (15 + 8) was 1:1, the quenching efficiency reached maximum. But with the molar ratio of SS and cDNA(8 + 8) increasing, the quenching efficiency increased continuously. Under the optimal conditions that we studied, the detection limit of thrombin by MB(8 + 8) and MB(15 + 8) was 0.19 and 1.2 nM, respectively. In addition, the assay proved to be selective, and the average recovery of thrombin detected by MB(8 + 8) and MB(15 + 8) in diluted serum was 95.4 and 94.5%, respectively.

Neuronal-driven glioma growth requires Gαi1 and Gαi3

Neuroligin-3 (NLGN3) is necessary and sufficient to promote glioma cell growth. The recruitment of Gαi1/3 to the ligand-activated receptor tyrosine kinases (RTKs) is essential for mediating oncogenic signaling.

Methods: Various genetic strategies were utilized to examine the requirement of Gαi1/3 in NLGN3-driven glioma cell growth.

Results: NLGN3-induced Akt-mTORC1 and Erk activation was inhibited by decreasing Gαi1/3 expression. In contrast ectopic Gαi1/3 overexpression enhanced NLGN3-induced signaling. In glioma cells, NLGN3-induced cell growth, proliferation and migration were attenuated by Gαi1/3 depletion with shRNA, but facilitated with Gαi1/3 overexpression. Significantly, Gαi1/3 silencing inhibited orthotopic growth of patient-derived glioma xenografts in mouse brain, whereas forced Gαi1/3-overexpression in primary glioma xenografts significantly enhanced growth. The growth of brain-metastatic human lung cancer cells in mouse brain was largely inhibited with Gαi1/3 silencing. It was however expedited with ectopic Gαi1/3 overexpression. In human glioma Gαi3 upregulation was detected, correlating with poor prognosis.

Conclusion: Gαi1/3 mediation of NLGN3-induced signaling is essential for neuronal-driven glioma growth.

[Impact of enhanced recovery after surgery strategy on early postoperative quality of recovery in patients undergoing laparoscopic surgery for gynecologic malignancy]

Objective: To investigate the impact of perioperative anesthesia management with enhanced recovery after surgery (ERAS) strategy on postoperative recovery in patients undergoing laparoscopic surgery for gynecologic malignancy. Methods: Ninety patients undergoing laparoscopic surgery for gynecologic malignancies from April 2018 to April 2019,aged 18-65 years,with American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, were recruited and randomly divided into two groups (n=45) using a random number table:ERAS group (group E) and control group (group C). Patients in group E received general anesthesia combined with transverses abdominis plane block and a series of interventions to optimize anesthetic and perioperative management, while patients in group C were treated with routine anesthesia management. Quality of Recovery-40 questionnaire (QoR-40) was administered to assess the early postoperative quality of recovery on 1 day before surgery, and at 24 and 48h after surgery. C-reactive protein (CRP) before and after the operation were evaluated. The incidence of nausea, vomiting and shivering, the time of first exhaust, ambulation, resumption of normal diet, postoperative hospital stay and complications were recorded. Results: The scores of QoR-40 [M(Q₁, Q₃)] in Group E were 175(171, 179) and 185(183, 189) at 24 h and 48 h after operation, which were higher than those in group C [162(160, 167) and 180(179, 183)] (both P<0.01). The levels of CRP in both group E and group C increased at 24 h and 72 h after operation. Moreover, the extent of increasing level of CRP in group C was much higher than that in group E [(39.8±18.0) mg/L vs (13.4±6.3) mg/L, (16.6±8.6) mg/L vs (6.7±2.5) mg/L] at 24 h and 48 h after operation (both P<0.01). Compared with group C, the numerical rating scale (NRS) for nausea decreased significantly in group E [0(0, 2) vs 3 (0, 5), P<0.01]. Meanwhile, the incidence of vomiting and shivering in group E was lower than that in group C [8.9% (4/45) vs 26.7% (12/45); 11.1% (5/45) vs 31.1% (14/45); both P<0.05]. The time of first exhaust, ambulation and resumption of normal diet in group E was (14±6) h, 6(6, 13) h and 1(1, 2) d, respectively, which was markedly shorter than that in group C [(25±10) h, 21(19, 27) h and 3(2, 3) d] (all P<0.01). Overall, the postoperative length of hospital stay reduced significantly for patients who followed the ERAS protocol [7(5, 11) d vs 10(7, 14) d, P<0.01]. The incidence of postoperative complications was 17.8% (8/45) and 37.8% (17/45) in group E and group C, respectively, with a significant difference (P<0.05). Conclusion: Implementation of ERAS anesthesia management in gynecologic oncology patients undergoing minimally invasive surgery alleviates perioperative discomfort, decreases surgical stress response, and improves the early postoperative quality of recovery.

Extracting neuronal activity signals from microscopy recordings of contractile tissue using B-spline Explicit Active Surfaces (BEAS) cell tracking

Ca2+ imaging is a widely used microscopy technique to simultaneously study cellular activity in multiple cells. The desired information consists of cell-specific time series of pixel intensity values, in which the fluorescence intensity represents cellular activity. For static scenes, cellular signal extraction is straightforward, however multiple analysis challenges are present in recordings of contractile tissues, like those of the enteric nervous system (ENS). This layer of critical neurons, embedded within the muscle layers of the gut wall, shows optical overlap between neighboring neurons, intensity changes due to cell activity, and constant movement. These challenges reduce the applicability of classical segmentation techniques and traditional stack alignment and regions-of-interest (ROIs) selection workflows. Therefore, a signal extraction method capable of dealing with moving cells and is insensitive to large intensity changes in consecutive frames is needed. Here we propose a b-spline active contour method to delineate and track neuronal cell bodies based on local and global energy terms. We develop both a single as well as a double-contour approach. The latter takes advantage of the appearance of GCaMP expressing cells, and tracks the nucleus' boundaries together with the cytoplasmic contour, providing a stable delineation of neighboring, overlapping cells despite movement and intensity changes. The tracked contours can also serve as landmarks to relocate additional and manually-selected ROIs. This improves the total yield of efficacious cell tracking and allows signal extraction from other cell compartments like neuronal processes. Compared to manual delineation and other segmentation methods, the proposed method can track cells during large tissue deformations and high-intensity changes such as during neuronal firing events, while preserving the shape of the extracted Ca2+ signal. The analysis package represents a significant improvement to available Ca2+ imaging analysis workflows for ENS recordings and other systems where movement challenges traditional Ca2+ signal extraction workflows.

Role of Surfactants Based on Fatty Acids in the Wetting Behavior of Solid-Oil-Aqueous Solution Systems

Surfactants based on fatty acids have attracted extensive attention thanks to their eco-friendly and pH-responsive features. Here, we studied two fatty acid-based surfactants that were paired with the same organic counterion but distinguished by their aliphatic chain lengths (monoethanolamine-oleic acid (MEA-OA) and monoethanolamine-lauric acid (MEA-LA)). Both surfactants exhibited the ability to lower the oil-water interfacial tension but lost their interfacial activity in a low-pH environment. We experimentally investigated their influence on the receding and spreading of oil droplets on solid surfaces. It was found that the interfacial tension reduction could decrease the static contact angle of the aqueous phase and hindered displacement dynamics during the oil droplet receding. Meanwhile, the interfacial activity was more likely to suppress the initiation of the oil droplet spreading due to the more stable thin-film forming prior to the spreading process. Nevertheless, the experimental results also exhibited that MEA-OA was more effective than MEA-LA in suppressing the receding dynamics and the spreading initiation even when they were characterized by similar interfacial tension values. Such an interesting observation could be attributed to the more considerable Marangoni flow in the solution of MEA-OA whose molecules have longer aliphatic chains. The insight from this study is expected to improve the knowledge on the molecular design for more efficient applications of fatty acid-based surfactants.

Integrating Population Variants and Protein Structural Analysis to Improve Clinical Genetic Diagnosis and Treatment in Nephrogenic Diabetes Insipidus

Congenital nephrogenic diabetes insipidus (NDI) is a rare genetic disorder characterized by renal inability to concentrate urine. We utilized a multicenter strategy to investigate the genotype and phenotype in a cohort of Chinese children clinically diagnosed with NDI from 2014 to 2019. Ten boys from nine families were identified with mutations in AVPR2 or AQP2 along with dehydration, polyuria-polydipsia, and severe hypernatremia. Genetic screening confirmed the diagnosis of seven additional relatives with partial or subclinical NDI. Protein structural analysis revealed a notable clustering of diagnostic mutations in the transmembrane region of AVPR2 and an enrichment of diagnostic mutations in the C-terminal region of AQP2. The pathogenic variants are significantly more likely to be located inside the domain compared with population variants. Through the structural analysis and in silico prediction, the eight mutations identified in this study were presumed to be disease-causing. The most common treatments were thiazide diuretics and non-steroidal anti-inflammatory drugs (NSAIDs). Emergency treatment for hypernatremia dehydration in neonates should not use isotonic saline as a rehydration fluid. Genetic analysis presumably confirmed the diagnosis of NDI in each patient in our study. We outlined methods for the early identification of NDI through phenotype and genotype, and outlined optimized treatment strategies.

[Laparoscopic circular stapled gastrointestinal anastomosis using novel device of sealed cap access after total laparoscopic gastrectomy]

Intracorporeal classic gastrointestinal anastomosis using circular stapler in totally laparoscopic gastrectomy (TLG) for gastric cancer requires intracorporeal anvil placement and suitable access for introduction of the circular stapler to the abdominal cavity without gas leak. The novel techniques for anvil placement have been updated, but there is no progress for proper access for circular stapler. In the study, intracorporeal circular-stapled gastrointestinal anastomosis were successfully accomplished using a novel device of sealed cap access with a central hole (WLB-60/70-60/100, Wuhan Widerep Medical Instrument Co.,Ltd, China) customized to the incision protection retractor for the simple and accessible introduction of the circular stapler and anvil under the optimal maintenance of pneumoperitoneum pressure in TLG. In these 3 cases, there was no gas leakage and the pneumoperitoneum was well maintained when performing the gastrointestinal anastomosis, and there was no transition to laparotomy or other anastomosis techniques. The result suggests that the sealed cap access could be a novel choice for introduction of the circular stapler to the abdominal cavity in order to obtain laparoscopic circular-stapled gastroin-testinal anastomosis in TLG.

CYP2C9*3/*3 Gene Expression Affects the Total and Free Concentrations of Valproic Acid in Pediatric Patients with Epilepsy

Purpose

To perform therapeutic drug monitoring (TDM) of total and free plasma valproic acid (VPA) concentrations in pediatric patients with epilepsy and to analyze related factors.

Patients and Methods

Pediatric epileptic patients treated in 2015-2019 in our hospital were assessed. Total and free plasma VPA concentrations were obtained by UPLC and LC-MS/MS, respectively. Regression analysis was performed to examine the associations of free plasma VPA with total plasma VPA and plasma protein binding rate. The impacts of individual situation, CYP2C9 genotype, and drug combination on VPA concentration were examined.

Results

Of the 251 patients, 81 had lower total concentrations than effective therapeutic levels; 86 and 31 patients had infections and central nervous system dysplasia, respectively. VPA's daily doses and free drug concentrations were significantly lower in the CYP2C9 *3/*3 genotype group versus the CYP2C9 *1/*3 and CYP2C9 *1/*1 groups (P<0.05). Free and total VPA concentrations were linked by Y = 0.0004 X² + 0.042 X + 0.3035 (r=0.6981); VPA plasma protein binding rate and free VPA concentration were related by Y = 0.0003 X² - 0.0127 X + 0.9777 (r=0.8136). Both total and free VPA concentrations were significantly decreased in patients simultaneously administered phenobarbital, meropenem and biapenem (P<0.05), with therapeutic failure after meropenem/biapenem co-administration.

Conclusion

Free VPA amounts have nonlinear relationships with total VPA amounts and plasma protein binding rate in epileptic children. Additionally, CYP2C9 *3/*3 expression affects VPA metabolism. Since phenobarbital affects VPA metabolism, TDM is recommended. Meanwhile, carbapenem-co-administration with VPA should be prohibited.

Topological Rainbow Concentrator Based on Synthetic Dimension

Synthetic dimension provides a new platform for realizing topological photonic devices. Here, we propose a method to realize a rainbow concentrator of topological photonic states based on the synthetic dimension concept. The synthetic dimension is constructed using a translational degree of freedom of the nanostructures inside the unit cell of a two-dimensional photonic crystal. The translational deformation induces a nontrivial topology in the synthetic dimension, which gives rise to robust interface states at different frequencies. The topological rainbow can trap states with different frequencies, controlled by tuning the spatial modulation of interface state group velocities. The operation frequency as well as the bandwidth of the topological rainbow can be easily tuned by controlling the band gap of the photonic crystal. The topological principle can be applied to photonic crystals of any symmetry and arbitrary material composition, as long as a complete band gap exists. This Letter provides a new and general scheme for the realization of a topological rainbow concentrator and will be useful for the development of topological photonic devices.

The histone acetyltransferase HBO1 functions as a novel oncogenic gene in osteosarcoma

HBO1 (KAT7 or MYST2) is a histone acetyltransferase that acetylates H3 and H4 histones.

Methods: HBO1 expression was tested in human OS tissues and cells. Genetic strategies, including shRNA, CRISPR/Cas9 and overexpression constructs, were applied to exogenously alter HBO1 expression in OS cells. The HBO1 inhibitor WM-3835 was utilized to block HBO1 activation.

Results:HBO1 mRNA and protein expression is significantly elevated in OS tissues and cells. In established (MG63/U2OS lines) and primary human OS cells, shRNA-mediated HBO1 silencing and CRISPR/Cas9-induced HBO1 knockout were able to potently inhibit cell viability, growth, proliferation, as well as cell migration and invasion. Significant increase of apoptosis was detected in HBO1-silenced/knockout OS cells. Conversely, ectopic HBO1 overexpression promoted OS cell proliferation and migration. We identified ZNF384 (zinc finger protein 384) as a potential transcription factor of HBO1. Increased binding between ZNF384 and HBO1 promoter was detected in OS cell and tissues, whereas ZNF384 silencing via shRNA downregulated HBO1 and produced significant anti-OS cell activity. In vivo, intratumoral injection of HBO1 shRNA lentivirus silenced HBO1 and inhibited OS xenograft growth in mice. Furthermore, growth of HBO1-knockout OS xenografts was significantly slower than the control xenografts. WM-3835, a novel and high-specific small molecule HBO1 inhibitor, was able to potently suppressed OS cell proliferation and migration, and led to apoptosis activation. Furthermore, intraperitoneal injection of a single dose of WM-3835 potently inhibited OS xenograft growth in SCID mice.

Conclusion: HBO1 overexpression promotes OS cell growth in vitro and in vivo.

Requirement of Gαi1 and Gαi3 in interleukin-4-induced signaling, macrophage M2 polarization and allergic asthma response

IL-4 induces Akt activation in macrophages, required for full M2 (alternative) polarization. We examined the roles of Gαi1 and Gαi3 in M2 polarization using multiple genetic methods.

Methods and Results: In MEFs and primary murine BMDMs, Gαi1/3 shRNA, knockout or dominant negative mutations attenuated IL-4-induced IL4Rα endocytosis, Gab1 recruitment as well as Akt activation, leaving STAT6 signaling unaffected. Following IL-4 stimulation, Gαi1/3 proteins associated with the intracellular domain of IL-4Rα and the APPL1 adaptor, to mediate IL-4Rα endosomal traffic and Gab1-Akt activation in BMDMs. In contrast, gene silencing of Gαi1/3 with shRNA or knockout resulted in BMDMs that were refractory to IL-4-induced M2 polarization. Conversely, Gαi1/3-overexpressed BMDMs displayed preferred M2 response with IL-4 stimulation. In primary human macrophages IL-4-induced Akt activation and Th2 genes expression were inhibited with Gαi1/3 silencing, but augmented with Gαi1/3 overexpression. In Gαi1/3 double knockout (DKO) mice, M2 polarization, by injection of IL-4 complex or chitin, was potently inhibited. Moreover, in a murine model of asthma, ovalbumin-induced airway inflammation and hyperresponsiveness were largely impaired in Gαi1/3 DKO mice.

Conclusion: These findings highlight novel and essential roles for Gαi1/3 in regulating IL-4-induced signaling, macrophage M2 polarization and allergic asthma response.

Clinical Features and Risk Factors of Fungal Peritonitis in Children on Peritoneal Dialysis

Objective: To analyse the clinical manifestations, aetiology, prognosis, and risk factors of fungal peritonitis (FP) in children on peritoneal dialysis (PD). Methods: Among 322 children undergoing PD at Children's Hospital of Fudan University, between January 2001 and December 2019, FP cases were retrospectively analysed and compared with those of bacterial peritonitis (BP) to analyse the risk factors of FP. Results: A total of 124 cases of peritonitis were treated, including 11 FP cases in 11 children (0.0019 episodes/patient^*month) and 113 BP cases in 64 children (0.02 episodes/patient^*month). Among the 11 FP cases, 7 cases (63.64%) were caused by Candida and Candida parapsilosis (5/7) was the most common pathogen of Candida. All FP patients were converted to haemodialysis (HD) and did not resume PD during follow-up. Two patients (18.2%) died after 6 months of HD due to heart failure, 2 patients underwent kidney transplant after 2 years of infection, and the other 7 patients were still on HD. The univariate analysis showed the usage rate of antibiotics in the month before the onset of peritonitis was higher (45.45 vs. 15.93%) and the mean serum albumin was lower (31.4 vs. 34.4 g/L) in the FP group when compared with BP group (P < 0.05), while multivariate analysis showed that serum albumin ≤ 30 g/L was an independent risk factor for FP (odds ratio 4.896, 95% confidence interval 1.335-17.961). Conclusion: FP is a rare complication of PD in children, but it is associated with high technique failure. Attention should be paid to hypoproteinaemia and antibiotic use in children on PD.

Determination of N-nitrosodimethylamine in Ranitidine Dosage Forms by ESI-LC-MS/MS; Applications for Routine Laboratory Testing

A practical high-performance liquid chromatography-mass spectrometry method was developed for the analysis of N-nitrosodimethylamine (NDMA) characterized as an impurity, in combination with reports of the carcinogen found in ranitidine samples. After simple extraction of ranitidine samples, all compounds were analyzed with a high-performance liquid chromatography-mass spectrometry. Sensitivity was enhanced by employing the ten-way valve switching technology, which was examined to allow NDMA to enter the mass spectrometry and cut out the ranitidine samples extremely. A good linear relationship was observed within 3-100 ng·mL^-1 (r = 0.9992). The validated approach was effectively used to evaluate the NDMA contents in ranitidine samples in circulation, which revealed a difference among 21 batches. Quantitative determination of NDMA was within the scope of 3.38-57.05 ng·mL^-1. Moreover, the contamination levels of NDMA in seven batches of products from six manufacturers were listed to exceed the acceptable daily intake. The sensitive method was verified to be appropriate to determine NDMA, even with low contents of NDMA in ranitidine products; the analysis of the selected samples reveals that some samples exceeded the national limit requirements. Therefore, it is worthwhile to conduct comprehensive quality control of the other drugs containing NDMA.

Preparation, evaluation and metabolites study in rats of novel amentoflavone-loaded TPGS/soluplus mixed nanomicelles

Amentoflavone (AMF) is a kind of biflavonoids existing in Ginkgo biloba leaves. It has many biological activities, such as antioxidant, anti-inflammatory, anti-bacterial, antiviral, hypoglycemic, anti-tumor and inducing apoptosis. However, its solubility and bioavailability are poor and there are a few studies on it in vivo. In this study, to improve its solubility and bioavailability, the nanomicelles were prepared with TPGS and soluplus as carriers for the first time. The particle size, Zeta potential, encapsulation efficiency, drug loading, stability, cytotoxicity, cellular uptake, and metabolites in rats were studied. Cytotoxicity, cellular uptake, and metabolites in rats of AMF-loaded TPGS/soluplus mixed micelles were compared with those of AMF. As a result, AMF-loaded TPGS/soluplus mixed micelles with a particle size of 67.33 ± 2.01 nm and Zeta potential of -0.84133 ± 0.041405 mV were successfully prepared. The encapsulation efficiency and drug loading of the mixed nanomicelles were 99.18 ± 0.76% and 2.47 ± 0.01%, respectively. The physical and chemical properties of the mixed micelles were stable within 60 d, and the cytotoxicity of the mixed micelles was much greater than that of AMF monomers. Thirty-four kinds of metabolites of AMF were identified in rats. The metabolites were mainly distributed in rat feces. No metabolites were detected in bile and plasma. 14 kinds of metabolites of the mixed micelles in rats were detected, including 11 in feces, 6 in urine, and 3 in plasma, which indicated that the bioavailability of AMF has been improved. And the toxicity to cancer cells was enhanced, which laid a foundation for the development of new drugs.

[Effects on learning and memory and mitochondrial energy metabolism in hippocampus of mice by subacute exposure to n-hexane]

Objective: To study the effects on learning and memory, mitochondrial energy metabolism and ATPase activity of hippocampus in mice with subacute exposure to n-hexane. Methods: The SPF 40 Kunming mice were randomly divided into low, middle and high dose groups and control groups according to different dosages. Each group consisted of 10 mice. The mice were given n-hexane by gavage, the mice in the low, middle and high dose groups were given 0.2 ml/d of n-hexane at concentrations of 500, 1000 and 2000 mg/kg respectively, while the mice in the control group were given 0.2 ml/d of cooking oil once a day for 28 days. The y-type maze test, the activity of ATP Enzyme, mitochondrial respiratory chain enzyme complex Ⅰ-IV, the mrna of mitochondrial fusion gene (MFn1, Mfn2) and fission gene (FIs1) in brain tissues were performed. Results: Except for the wrong reaction times of low-dose exposure group in the first test, there existed significantly different in the first and second Y-maze tests in exposure groups and control group (P<0.05) ; in low, middle and high-dose group, the Na(+)-K(+)-ATPase activities were (8.27±2.65) , (5.38±1.55) , (3.55±1.69) μmol/gprot/h, and Ca(2+)-Mg(2+)-ATPase activities were (10.32±2.96) , (7.19±1.94) and (4.49±1.33) μmol/gprot/h, respectively. Compared with those in control group, the activities of Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase decreased significantly in middle-dose group and high-dose group (P<0.05) . Compared with those in control group, the activities of mitochondrial respiratory chain enzyme complex I-IV in each dose group were significantly decreased (P<0.05) . The expressions of Mfn1mRNA and Mfn2mRNA in each dose group was significantly lower than those in control group (P<0.05) . Conclusion: Subacute exposure to n-hexane can result in the decrease of activities of mitochondrial respiratory chain enzyme complex in hippocampus of mice, which may lead to the disorder of mitochondrial energy metabolism by the decrease of ATPase activity and the imbalance of mitochondrial fusion-division, which must be one of the mechanisms of impairment of learning and memory of mice induced by n-hexane.