Prevention and treatment of noise-induced hearing loss and cochlear synapse degeneration by potassium channel blockers in vivo.

Noise can induce hearing loss. In particularly, noise can induce cochlear synapse degeneration leading to hidden hearing loss, which is the most common type of hearing disorders in the clinic. Currently, there is no pharmacological treatment, particularly, no post-exposure (i.e., therapeutic) treatment available in the clinic. Here, we report that systematic administration of K + channel blockers before or after noise exposure could significantly attenuate NIHL and synapse degeneration. After systematic administration of a general K-channel blocker tetraethylammonium (TEA), the elevation of auditory brainstem response (ABR) thresholds after noise-exposure significantly reduced, and the active cochlear mechanics significantly improved. The therapeutic effect was further improved as the post-exposure administration time extending to 3 days. BK channel is a predominant K + channel in the inner hair cells. Systematic administration of a BK channel blocker GAL-021 after noise exposure also ameliorated hearing loss and improved hearing behavioral responses tested by acoustic startle response (ASR). Finally, both TEA and GAL-021 significantly attenuated noise-induced ribbon synapse degeneration. These data demonstrate that K + -channel blockers can prevent and treat NIHL and cochlear synapse degeneration. Our finding may aid in developing therapeutic strategies for post-exposure treatment of NIHL and synapse degeneration. Significance Statement: Noise is a common deafness factor affecting more 100 million people in the United States. So far, there is no pharmacological treatment available. We show here that administration of K + channel blockers after noise exposure could attenuate noise-induced hearing loss and synapse degeneration, and improved behavioral responses. This is the first time to real the K + channel blockers that could treat noise-induced hearing loss and cochlear synaptopathy after noise exposure.

Potential effects of nutrition-induced alteration of gut microbiota on inflammatory bowel disease: A review.

Inflammatory bowel disease (IBD), mainly comprising ulcerative colitis and Crohn's disease, is a group of gradually progressive diseases bringing significant mental anguish and imposes serious economic burdens. Interplay of genetic, environmental, and immunological factors have been implicated in its pathogenesis. Nutrients, as crucial environmental determinants, mainly encompassing carbohydrates, fats, proteins, and micronutrients, are closely related to the pathogenesis and development of IBD. Nutrition is essential for maintaining the dynamic balance of intestinal eco-environments to ensure intestinal barrier and immune homeostasis, while this balance can be disrupted easily by maladjusted nutrition. Research has firmly established that nutrition has the potential to shape the composition and function of gut microbiota to affect the disease course. Unhealthy diet and eating disorders lead to gut microbiota dysbiosis and further destroy the function of intestinal barrier such as the disruption of membrane integrity and increased permeability, thereby triggering intestinal inflammation. Notably, appropriate nutritional interventions, such as the Mediterranean diet, can positively modulate intestinal microecology, which may provide a promising strategy for future IBD prevention. In this review, we provide insights into the interplay between nutrition and gut microbiota and its effects on IBD and present some previously overlooked lines of evidence regarding the role of derived metabolites in IBD processes, such as trimethylamine N-oxide and imidazole propionate. Furthermore, we provide some insights into reducing the risk of onset and exacerbation of IBD by modifying nutrition and discuss several outstanding challenges and opportunities for future study.

Comprehensive analysis of anoikis-related genes in diagnosis osteoarthritis: based on machine learning and single-cell RNA sequencing data.

Osteoarthritis (OA) is a degenerative disease closely associated with Anoikis. The objective of this work was to discover novel transcriptome-based anoikis-related biomarkers and pathways for OA progression.The microarray datasets GSE114007 and GSE89408 were downloaded using the Gene Expression Omnibus (GEO) database. A collection of genes linked to anoikis has been collected from the GeneCards database. The intersection genes of the differential anoikis-related genes (DEARGs) were identified using a Venn diagram. Infiltration analyses were used to identify and study the differentially expressed genes (DEGs). Anoikis clustering was used to identify the DEGs. By using gene clustering, two OA subgroups were formed using the DEGs. GSE152805 was used to analyse OA cartilage on a single cell level. 10 DEARGs were identified by lasso analysis, and two Anoikis subtypes were constructed. MEgreen module was found in disease WGCNA analysis, and MEturquoise module was most significant in gene clusters WGCNA. The XGB, SVM, RF, and GLM models identified five hub genes (CDH2, SHCBP1, SCG2, C10orf10, P FKFB3), and the diagnostic model built using these five genes performed well in the training and validation cohorts. analysing single-cell RNA sequencing data from GSE152805, including 25,852 cells of 6 OA cartilage.

Cx26 heterozygous mutations cause hyperacusis-like hearing oversensitivity and increase susceptibility to noise.

Gap junction gene GJB2 (Cx26) mutations cause >50% of nonsyndromic hearing loss. Its recessive hetero-mutation carriers, who have no deafness, occupy ~10 to 20% of the general population. Here, we report an unexpected finding that these heterozygote carriers have hearing oversensitivity, and active cochlear amplification increased. Mouse models show that Cx26 hetero-deletion reduced endocochlear potential generation in the cochlear lateral wall and caused outer hair cell electromotor protein prestin compensatively up-regulated to increase active cochlear amplification and hearing sensitivity. The increase of active cochlear amplification also increased sensitivity to noise; exposure to daily-level noise could cause Cx26+/- mice permanent hearing threshold shift, leading to hearing loss. This study demonstrates that Cx26 recessive heterozygous mutations are not "harmless" for hearing as previously considered and can cause hyperacusis-like hearing oversensitivity. The data also indicate that GJB2 hetero-mutation carriers are vulnerable to noise and should avoid noise exposure in daily life.

Effect of Wrist-Ankle Acupuncture on Postoperative Analgesia after Total Knee Arthroplasty.

OBJECTIVE: To evaluate the effect of wrist-ankle acupuncture (WAA) in pain and functional recovery after total knee arthroplasty (TKA). METHODS: From June to September 2020, 94 participants were included from the Second Hospital of Tangshan and randomly assigned to the WAA group (47 cases) and the sham WAA group (47 cases) by a random number table, receiving real or sham WAA treatment, respectively. The primary outcome measure involved the visual analogue scale (VAS) scores at rest and in motion. The secondary outcomes involved the range of motion (ROM) of the knee joints, straight-leg raising time, postoperative weight-bearing time, sufentanil consumption within 48 h of patient-controlled analgesia (PCA) pump, length of hospital stay, and postoperative complications. RESULTS: The VAS scores on the 3rd, 5th, and 7th postoperative days at rest and in motion was significantly lower in the WAA group than that of the sham WAA group (P<0.01). The ROM on the 1st, 2nd, and 3rd PODs was significantly higher in the WAA group than that of the sham WAA group (P<0.01). In comparison to the sham WAA group, the sufentanil consumption within 48 h of PCA pump was significantly less in the WAA group (156.3 ± 12.2 µg vs. 128.8 ± 9.8 µg, P<0.01). There was no significant difference in active straight-leg raising time, postoperative weight-bearing time, length of hospital stay, and postoperative complications between the two groups (P>0.05). CONCLUSIONS: WAA could alleviate post-TKA pain, improve knee joint function, and reduce the sufentanil consumption within 48 h of PCA pump. WAA is a safe and effective treatment in the perioperative analgesic management for TKA.

Moxibustion plus Acupuncture for the Treatment of Poststroke Shoulder Pain: A Randomized Controlled Pilot Study.

BACKGROUND: In China, 45% of stroke patients suffer from poststroke shoulder pain, which brings about many obstacles to further rehabilitation. To date, there have been a few studies evaluating the effects of acupuncture or massage in treating poststroke shoulder pain, and good effects have been shown. However, better clinical treatments are still needed. OBJECTIVE: To explore a more effective treatment for poststroke shoulder pain, the clinical effects of moxibustion plus acupuncture were assessed. METHODS: Sixty patients were randomly divided into the control and intervention groups. The control group received a standard stroke treatment protocol including acupuncture, and the intervention group was given moxibustion combined with acupuncture. The visual analogue scale (VAS), National Institutes of Health Stroke Scale (NIHSS), Fugl-Meyer motor assessment, Barthel Index, and 17-item Hamilton Rating Scale for Depression (HAMD-17) were applied, and differences were analyzed. RESULTS: After 4 weeks of treatment, compared with the control group, the intervention group demonstrated significant improvement in Fugl-Meyer motor assessment and HAMD-17 (both p < 0.01) as well as in the VAS, NIHSS, and Barthel Index (all p < 0.05). CONCLUSION: Moxibustion plus acupuncture treatment can alleviate poststroke shoulder pain, improve upper limb motor function and the ability to perform activities of daily living, and relieve patients' depression.

Efferent neurons control hearing sensitivity and protect hearing from noise through the regulation of gap junctions between cochlear supporting cells.

It is critical for hearing that the descending cochlear efferent system provides a negative feedback to hair cells to regulate hearing sensitivity and protect hearing from noise. The medial olivocochlear (MOC) efferent nerves project to outer hair cells (OHCs) to regulate OHC electromotility, which is an active cochlear amplifier and can increase hearing sensitivity. Here, we report that the MOC efferent nerves also could innervate supporting cells (SCs) in the vicinity of OHCs to regulate hearing sensitivity. MOC nerve fibers are cholinergic, and acetylcholine (ACh) is a primary neurotransmitter. Immunofluorescent staining showed that MOC nerve endings, presynaptic vesicular acetylcholine transporters (VAChTs), and postsynaptic ACh receptors were visible at SCs and in the SC area. Application of ACh in SCs could evoke a typical inward current and reduce gap junctions (GJs) between them, which consequently enhanced the direct effect of ACh on OHCs to shift but not eliminate OHC electromotility. This indirect, GJ-mediated inhibition had a long-lasting influence. In vivo experiments further demonstrated that deficiency of this GJ-mediated efferent pathway decreased the regulation of active cochlear amplification and compromised the protection against noise. In particular, distortion product otoacoustic emission (DPOAE) showed a delayed reduction after noise exposure. Our findings reveal a new pathway for the MOC efferent system via innervating SCs to control active cochlear amplification and hearing sensitivity. These data also suggest that this SC GJ-mediated efferent pathway may play a critical role in long-term efferent inhibition and is required for protection of hearing from noise trauma.NEW & NOTEWORTHY The cochlear efferent system provides a negative feedback to control hair cell activity and hearing sensitivity and plays a critical role in noise protection. We reveal a new efferent control pathway in which medial olivocochlear efferent fibers have innervations with cochlear supporting cells to control their gap junctions, therefore regulating outer hair cell electromotility and hearing sensitivity. This supporting cell gap junction-mediated efferent control pathway is required for the protection of hearing from noise.

Early Functional and Cognitive Declines Measured by Auditory-Evoked Cortical Potentials in Mice With Alzheimer's Disease.

Alzheimer's disease (AD) is characterized by a progressive loss of memory and cognitive decline. However, the assessment of AD-associated functional and cognitive changes is still a big challenge. Auditory-evoked cortical potential (AECP) is an event-related potential reflecting not only neural activation in the auditory cortex (AC) but also cognitive activity in the brain. In this study, we used the subdermal needle electrodes with the same electrode setting as the auditory brainstem response (ABR) recording and recorded AECP in normal aging CBA/CaJ mice and APP/PS1 AD mice. AECP in mice usually appeared as three positive peaks, i.e., P1, P2, and P3, and three corresponding negative peaks, i.e., N1, N2, and N3. In normal aging CBA mice, the early sensory peaks P1, N1, and P2 were reduced as age increased, whereas the later cognitive peaks N2, P3, and N3 were increased or had no changes with aging. Moreover, the latency of the P1 peak was increased as age increased, although the latencies of later peaks had a significant reduction with aging. In AD mice, peak P1 was significantly reduced in comparison with wild-type (WT) littermates at young ages, proceeding AD phenotype presentation. In particular, the later cognitive peak P3 was diminished after 3 months old, different from the normal aging effect. However, the latencies of AECP peaks in AD mice generally had no significant delay or changes with aging. Finally, consistent with AECP changes, the accumulation of amyloid precursor protein (APP) at the AC was visible in AD mice as early as 2 months old. These data suggest that AECP could serve as an early, non-invasive, and objective biomarker for detecting AD and AD-related dementia (ADRD).

2D-layered Mg(OH)2 material adsorbing cellobiose via interfacial chemical coupling and its applications in handling toxic Cd2+ and UO22+ ions.

The interfacial chemistry of nanocomposite materials is of overarching importance in the separation and purification science; moreover, its understanding helps to guide synthesis, clarify structure-property relationship and unearth novel applications. However, the composites feature rather complicated local structures and hydrogen bonds are often involved in the interface and the vicinity of active sites. In this regard, density functional theory first-principle calculations associated with experimental study have synergistically examined two-dimensional (2D) magnesium hydroxide material with different layers and their adsorption toward cellobiose. Hydrogen bonds are found responsible for the interfacial coupling, which make it vital to cover the dispersion correction in the calculation. The average adsorption energy ranges from -0.29 to -0.35 eV, falling well within the range of reported hydrogen-bonding strength. On the basis of calculated structural/interfacial properties and experimental findings, the 2D Mg(OH)2 in terms of three-layer model was unraveled to substitute toxic Cd2+ ion and sorb radioactive UO22+ that is coordinated by water and hydroxyl groups. These reactions are thermodynamically feasible. The ion-exchanging mechanism was proposed for cadmium removal and the outer-sphere adsorption one for uranium extraction.

[Effects of Long Non-coding RNA-TUC338 on the Migration and Proliferation of Lymphoma Cells via PI3K/AKT Signaling Pathway].

OBJECTIVE: To investigate the effect of long non-coding RNA-TUC338 on the proliferation and migration of lymphoma cells. METHODS: The expression of TUC338 in different lymphoma cells was detected by fluorescence quantitative PCR, cell proliferation by sulforhodamine B (SRB) assay, migration of lymphoma cells by transwell assay, and protein expression in PI3K/AKT signaling pathway by Western blot. RESULTS: The expression levels of TUC338 in lymphoma cells Daudi, U937, BC-3, and Raji significantly increased in comparison with human normal T lymphocytes H9 (t=13.277, 10.103, 16.200, and 26.687, P=0.002, 0.005, 0.001, and 0.000). Compared with NC-siRNA group, the number of cells crossing the chamber of TUC338-siRNA group was significantly reduced (t=30.508, P=0.000), the protein expression levels of p-PI3K and p-AKT significantly decreased (t=16.872 and 18.371, P=0.000 and 0.000), and OD530 absorbance values at 24 h, 48 h, and 72 h were significantly lower (P<0.05). CONCLUSION: The expression of TUC338 significantly increases in lymphoma cells, and silence of TUC338 effectively inhibits the activation of PI3K/AKT signaling pathway, thereby inhibiting the proliferation and migration of lymphoma cells, which has a potential application value in diagnosis and treatment of lymphoma.

A comparison between deep learning convolutional neural networks and radiologists in the differentiation of benign and malignant thyroid nodules on CT images.

INTRODUCTION: We designed 5 convolutional neural network (CNN) models and ensemble models to differentiate malignant and benign thyroid nodules on CT, and compared the diagnostic performance of CNN models with that of radiologists. MATERIAL AND METHODS: We retrospectively included CT images of 880 patients with 986 thyroid nodules confirmed by surgical pathology between July 2017 and December 2019. Two radiologists retrospectively diagnosed benign and malignant thyroid nodules on CT images in a test set. Five CNNs (ResNet50, DenseNet121, DenseNet169, SE-ResNeXt50, and Xception) were trained-validated and tested using 788 and 198 thyroid nodule CT images, respectively. Then, we selected the 3 models with the best diagnostic performance on the test set for the model ensemble. We then compared the diagnostic performance of 2 radiologists with 5 CNN models and the integrated model. RESULTS: Of the 986 thyroid nodules, 541 were malignant, and 445 were benign. The area under the curves (AUCs) for diagnosing thyroid malignancy was 0.587-0.754 for 2 radiologists. The AUCs for diagnosing thyroid malignancy for the 5 CNN models and ensemble model was 0.901-0.947. There were significant differences in AUC between the radiologists' models and the CNN models (p < 0.05). The ensemble model had the highest AUC value. CONCLUSIONS: Five CNN models and an ensemble model performed better than radiologists in distinguishing malignant thyroid nodules from benign nodules on CT. The diagnostic performance of the ensemble model improved and showed good potential.

Excess extracellular K+ causes inner hair cell ribbon synapse degeneration.

Inner hair cell (IHC) ribbon synapses are the first synapse in the auditory system and can be degenerated by noise and aging, thereby leading to hidden hearing loss (HHL) and other hearing disorders. However, the mechanism underlying this cochlear synaptopathy remains unclear. Here, we report that elevation of extracellular K+, which is a consequence of noise exposure, could cause IHC ribbon synapse degeneration and swelling. Like intensity dependence in noise-induced cochlear synaptopathy, the K+-induced degeneration was dose-dependent, and could be attenuated by BK channel blockers. However, application of glutamate receptor (GluR) agonists caused ribbon swelling but not degeneration. In addition, consistent with synaptopathy in HHL, both K+ and noise exposure only caused IHC but not outer hair cell ribbon synapse degeneration. These data reveal that K+ excitotoxicity can degenerate IHC ribbon synapses in HHL, and suggest that BK channel may be a potential target for prevention and treatment of HHL.

Xiaoyaosan Produces Antidepressant Effects in Rats via the JNK Signaling Pathway.

BACKGROUND: Xiaoyaosan (XYS) has achieved definite curative effects in clinic. However, the mechanism is not clear. Previous studies of our team indicated XYS improved anxiety-like behaviors through inhibiting c-Jun N-terminal kinase (JNK) signaling pathway of hippocampus. OBJECTIVES: In the study, we explored whether the JNK signaling pathway is involved in the mechanism of XYS treating depression. METHOD: Forty-eight rats were divided randomly into 4 groups (n = 12): the control group (deionized water, p.o.), the model group (deionized water, p.o.), the fluoxetine group (2.08 mg/kg/day, p.o.), and the XYS group (3.9 g/kg/day, p.o.). All rats except for the control group were given continuous 21 days of chronic immobilization stress (CIS; 3 h/day). On day 29, the body weights and the behavioral tests, including the novelty suppressed feeding test, the open field test, and the elevated plus maze test, were measured. On day 30, all the rats were sacrificed, and three indices of the JNK signaling pathway were tested by Western blot. RESULTS: The body weight and behavioral tests of all groups indicated that 21 days of CIS induced depression-like behaviors. After 21 days of treatment with fluoxetine and XYS, changes were seen in body weight, behaviors, and JNK, phosphorylated JNK (P-JNK), and phosphorylated c-Jun (P-c-Jun) levels in the hippocampus. CONCLUSIONS: XYS ameliorated the depression-like behaviors, potentially through affecting the JNK signaling pathway in the hippocampus.

Effect of simvastatin on bovine intramuscular and subcutaneous adipocytes proliferation and gene expression in vitro.

Simvastatin (SIM) is a widely used anticholesterolemic drug that blocks the biosynthesis of cholesterol. However, SIM also has pleiotropic effects on 3-hydroxy-3-methyglutary-CoA reductase (HMGR), cholesteryl ester transfer protein (CETP), and lipoprotein lipase (LPL), which are important genes in the cholesterol biosynthesis and transport processes. We investigated the effects of different concentrations of SIM on the mRNA expression of these genes in bovine intramuscular and subcutaneous adipocytes from the longissimus dorsi muscle and subcutaneous fat tissues of Luxi Yellow cattle. The results showed that SIM treatment showed dose-dependent toxicity on normal adipose cells, but no effect on cell proliferation. SIM decreased HMGR expression in a dose-dependent manner but showed no significant effect on CETP and LPL expression. Thus, SIM may lower the cholesterol content by decreasing the HMGR expression level, but CETP and LPL may be regulated through other mechanisms, which require further investigation.

Hearing loss is an early biomarker in APP/PS1 Alzheimer's disease mice.

Alzheimer's disease (AD) is a neurodegenerative disease characterized by a progressive loss of memory and cognitive decline. Over the last decade, it has been found that defects in sensory systems could be highly associated with AD. Hearing is an important neural sense. However, little is known about hearing functional changes in AD. In this study, APP/PS1 AD mice (Jackson Lab: Stack No. 004462) were used. Hearing function was assessed by auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and cochlear microphonics (CM) recordings. Wild-type (WT) littermates served as control. We found that APP/PS1 AD mice measured as ABR threshold had hearing loss. The hearing loss appeared at high frequency as early as 2 months old, prior to the reported occurrence of spatial learning deficit at 6-7 months of age in this AD mouse model. The hearing loss was progressive and extended from high frequency to low frequency. At 3-4 months old, the hearing loss appeared in the whole-frequency range. Moreover, the wave IV and V in the super-threshold ABR were eliminated, indicating substantial impairment in inferior colliculus, nuclei of lateral lemniscus, and medial geniculate body in the upper brainstem. DPOAE in APP/PS1 AD mice was also reduced. However, there was no reduction in CM in APP/PS1 mice. These data demonstrate that unlike age-related hearing loss APP/PS1 AD mice have early onset of hearing loss. These data also suggest that hearing function testing could provide a simple, sensitive, non-invasive screen-tool for early detecting AD and localizing lesion.

Protective effects of astaxanthin on lipopolysaccharide-induced inflammation in bovine endometrial epithelial cells†.

Astaxanthin (AST), a natural antioxidant carotenoid, has been shown to exert anti-inflammatory effects. However, to our knowledge, no study has specifically addressed the potential protective effects of AST against bovine endometritis. The purpose of this study was to examine whether treatment with AST could protect endometrial epithelial cells against lipopolysaccharide (LPS)-induced inflammatory injury. Treatment of bovine endometrial (BEND) epithelial cell line with AST reduced LPS-induced production of interleukin-6 and tumor necrosis factor-alpha, increased the cellular activity of superoxide dismutase and catalase, decreased the proportion of apoptotic cells, and promoted the production of insulin-like growth factor and epithelial growth factor. The effects of AST were mediated through the downregulation of B-cell lymphoma 2 (Bcl-2) associated X, apoptosis regulator (Bax), and cleaved caspase-3 and through the upregulation of Bcl-2. Moreover, AST significantly increased the expression of the tight junction proteins (TJP) claudin, cadherin-1, and TJP1, which play an essential role in the maintenance of host endometrial defense barrier against pathogen infection. Collectively, these results demonstrated that treatment with AST protected against oxidative stress, prevented cell apoptosis, promoted BEND cells viability, and increased the production of growth factors, in addition to activating the endometrial defense barrier. Therefore, AST is a promising therapeutic agent for the prevention and treatment of endometritis. This finding is of utmost importance in the present times when the excessive use of antibiotics has resulted in the development of antibiotic-resistant bacteria.

Redox and structural properties of accessible actinide(ii) metallocalixarenes (Ac to Pu): a relativistic DFT study.

The redox properties of actinides play a significant role in manipulating organometallic chemistry and energy/environment science, for being involved in fundamental concepts (oxidation state, bonding and reactivity), nuclear fuel cycles and contamination remediation. Herein, a series of trans-calix[2]pyrrole[2]benzene (H2L2) actinide complexes (An = Ac-Pu, and oxidation states of +II and +III) have been studied by relativistic density functional theory. Reduction potentials (E 0) of [AnL2]+/[AnL2] were computed within -2.45 and -1.64 V versus Fc+/Fc in THF, comparable to experimental values of -2.50 V for [UL1e]/[UL1e]- (H3L1e = (Ad,MeArOH)3mesitylene and Ad = adamantyl) and -2.35 V for [U(CpiPr)2]+/[U(CpiPr)2] (CpiPr = C5 iPr5). The E 0 values show an overall increasing trend from Ac to Pu but a break point at Np being lower than adjacent elements. The arene/actinide mixed reduction mechanism is proposed, showing arenes predominant in Ac-Pa complexes but diverting to metal-centered domination in U-Pu ones. Besides being consistent with previously reported those of AnIII/AnII couples, the changing trend of our reduction potentials is corroborated by geometric data, topological analysis of bonds and electronic structures as well as additional calculations on actinide complexes ligated by tris(alkyloxide)arene, silyl-cyclopentadiene and octadentate Schiff-base polypyrrole in terms of electron affinity. The regularity would help to explore synthesis and property of novel actinide(ii) complex.

Systematic study of the quality and safety of chilled pork from wet markets, supermarkets, and online markets in China.

BACKGROUND: With increasing media coverage of food safety incidents, such as that of clenbuterol residues in pork, food safety has become a major public health concern in China. Rapidly developing online markets attract increasing numbers of Chinese consumers to purchase food on the Internet. However, the quality and safety of food sold online are uncertain and are less reported on. OBJECTIVE: This research aimed to systematically study the quality and safety of chilled pork from wet markets, supermarkets, and online markets in China. RESULTS: The chilled pork samples from online markets were fresher than those from wet markets and supermarkets based on the surface redness (a* value). Chilled pork contained high levels of nutritional elements, especially the magnesium and phosphorus levels in samples from online markets. The levels of heavy metal element residues and veterinary drug residues in all chilled pork samples were within the standards limits. In addition, huge differences existed in the quality and freshness of the chilled pork samples from online markets according to principal component analysis (PCA). CONCLUSIONS: Most chilled pork sold in Chinese markets was qualified and safe. It is necessary to establish an effective online market supervision system for chilled pork.