Oridonin employs interleukin 1 receptor type 2 to treat noise-induced hearing loss by blocking inner ear inflammation.

NOD-like receptor protein 3 (NLRP3) inflammasomes trigger the inflammatory cascades and participate in various inflammatory diseases, including noise-induced hearing loss (NIHL) caused by oxidative stress. Recently, the anti-inflammatory traditional medicine oridonin (Ori) has been reported to provide hearing protection in mice after noise exposure by blocking the NLRP3-never in mitosis gene A-related kinase 7 (NEK7)-inflammasome complex assembly. Using RNA sequencing analysis, we further elucidated that interleukin 1 receptor type 2 (IL1R2) may be another crucial factor regulated by Ori to protect NIHL. We observed that IL1R2 expression was localized in spiral ganglion neurons, inner and outer hair cells, in Ori-treated mouse cochleae. Additionally, we confirmed that ectopic overexpression of IL1R2 in the inner ears of healthy mice using an adeno-associated virus delivery system significantly reduced noise-induced ribbon synapse lesions and hearing loss by blocking the "cytokine storm" in the inner ear. This study provides a novel theoretical foundation for guiding the clinical treatment of NIHL.

Clinical Efficacy and Safety Analysis of PD-1/PD-L1 Inhibitor vs. Chemotherapy in the Treatment of Advanced Non-Small-Cell Lung Cancer: A Systematic Review and Meta-Analysis.

Objective: To systematically evaluate the efficacy and safety of pembrolizumab (PD-1/PD-L inhibitor) and adjuvant chemotherapy to treat NSCLC and provide evidence-based reference for clinical use. Methods: By searching the Cochrane Library, EMBASE, PubMed, and Web of Science, according to the inclusion criteria, literature selection, data extraction, and quality evaluation were carried out for the included literature. The I 2 test was used to evaluate heterogeneity between studies, and the meta-analysis was performed using RevMan 5.3 software provided by Cochrane. Results: Finally, 14 relevant documents meeting the standards were included. It is a statistical difference in one-year survival rate [OR = 1.50, 95% CI (1.28, 1.76), P < 0.00001, I 2 = 0%, Z = 4.99]; overall response rate[OR =1.57, 95% CI (1.29, 1.90), P < 0.00001, I 2 = 0%, Z = 4.58]; progression-free survival [OR = 2.99, 95% CI (2.29, 3.91), P < 0.00001, I 2 = 26%, Z = 8.00]; and overall survival [OR = 1.38, 95% CI (1.07, 1.78), P = 0.01, I 2 = 46%, Z = 2.50] and reduces the incidence of adverse drug reactions [OR = 2.54, 95% CI (1.99, 3.25), P < 0.00001, I 2 = 69%, Z = 7.43]. Conclusion: Pembrolizumab adjuvant chemotherapy is effective in the treatment of advanced NSCLC, but attention should be paid to the occurrence of adverse reactions in clinical. Due to the limitations of the methodology included in the study, this conclusion required more validation of large-sample RCT.

Crosstalk between ILC2s and Th2 CD4+ T Cells in Lung Disease.

Cytokine secretion, such as interleukin-4 (IL-4), IL-5, IL-9, IL-13, and amphiregulin (Areg), by type 2 innate lymphoid cells (ILC2s) is indispensable for homeostasis, remodeling/repairing tissue structure, inflammation, and tumor immunity. Often viewed as the innate cell surrogate of T helper type 2 (Th2) cells, ILC2s not only secrete the same type 2 cytokines, but are also inextricably related to CD4+T cells in terms of cell origin and regulatory factors, bridging between innate and adaptive immunity. ILC2s interact with CD4+T cells to play a leading role in a variety of diseases through secretory factors. Here, we review the latest progress on ILC2s and CD4+T cells in the lung, the close relationship between the two, and their relevance in the lung disease and immunity. This literature review aids future research in pulmonary type 2 immune diseases and guides innovative treatment approaches for these diseases.

Circular RNA circ_0023404 serves as a miR-636 sponge to promote malignant behaviors in cervical cancer cells through upregulation of CYP2S1.

Cervical cancer is the most common malignant gynecological tumor. Circular RNA (circRNA) circ_0023404 is reported to be upregulated in cervical cancer cells. This aim is to explore the role and mechanism of circ_0023404 in cervical cancer. circ_0023404, microRNA-636 (miR-636), and cytochrome P450 2S1 (CYP2S1) levels were detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, migration, invasion, and apoptosis were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EDU) assay, colony formation assay, transwell assay, and cytometry assay. Protein levels of cyclin D1, matrix metallopeptidase 9 (MMP9), Bcl-2-associated X protein (Bax), and CYP2S1 were examined by western blot assay. The binding relationship between miR-636 and circ_0023404 or CYP2S1 was predicted by Circinteractome or targetscan, and then verified by a dual-luciferase reporter assay and RNA pull-down assay. circ_0023404 and CYP2S1 expression were increased, and miR-636 was decreased in cervical cancer tissues and cells. Moreover, circ_0023404 knockdown could repress proliferation, migration, invasion, and promote apoptosis of cervical cancer cells in vitro. Mechanically, circ_0023404 could regulate CYP2S1 expression by sponging miR-636. circ_0023404 silencing could attenuate the progression of cervical cancer cells partly by targeting the miR-636/CYP2S1 axis, hinting at a promising therapeutic target for cervical cancer.

Canalostomy is an ideal surgery route for inner ear gene delivery in big animal model.

Background: Inner gene therapy offers great promises as a potential treatment for hearing loss. Aims/objectives: One of the critical determinants of the success of inner ear gene therapy is to find a delivery method which results in consistent transduction efficiency of targeted cell types while minimizing hearing loss. Material and methods: Surgery was performed only in the right ear of each Bama miniature pig, and the left ear served as a control. The gene delivery to inner ear via round window membrane (RWM) and posterior semicircular canal (PSC) approach was performed with the viral vector AAV1-CMV-GFP. Results: The gene delivery through RWM and the PSC (canalostomy) is able to perfuse the inner ear. Conclusions and significance: The easy anatomic identification of the PSC, as to RWM, as well as minimal manipulation of the temporal bone required, make this surgical approach an attractive option for inner ear gene delivery in big animal model.

Acid stimulation-induced semi-pluripotent characteristics in human somatic cells.

BACKGROUND: Clinical trials of cell-based therapies using induced pluripotent stem (iPS) cells have already been started for several neurological diseases. OBJECTIVE: The purpose of the present study was to explore the characteristics and differentiation of somatic cells in vitro undergoing a low pH treatment, so as to provide new therapeutic strategies for treating sensorineural hearing loss. METHODS: Somatic cells were treated with low pH solution to alter their characteristics. In addition, a mouse model of the cochlear lesion was constructed using bilirubin. Subsequently, the characteristics and therapeutic effect of somatic cells undergoing low pH treatment were examined by morphology, alkaline phosphatase (AKP) activity, immunofluorescence assay and q-PCR. RESULTS: The cells in the experimental group grew better than those in the control group. The AKP activity in the experimental group was higher than that in the control group. The expression of Nanog and Oct4 was both positive in the two groups. When the cells were changed to neurobasal medium, the marker of nestin was positive. CONCLUSION: The human somatic cells undergoing a low pH treatment showed the similar characteristics as those of iPS cells, although the functions and therapeutic effect of these altered human somatic cells need to be further studied.

Flavonones from Penthorum chinense Ameliorate Hepatic Steatosis by Activating the SIRT1/AMPK Pathway in HepG2 Cells.

Pinocembrin-7-O-ß-d-glucoside (PCBG), pinocembrin (PCB), and 5-methoxy-pinocembrin-7-O-ß-d-glucoside (MPG) are three flavonones isolated from Penthorum chinense Pursh (P. chinense). The effects of the three flavonones on hepatic steatosis and their molecular mechanisms in HepG2 cells were investigated in this study for the first time. A model of hepatic steatosis in HepG2 cells was induced by free fatty acid (FFA), and co-treated with the three flavonones as mentioned. Intracellular lipid droplets were detected by Oil Red O staining. PCB, PCBG, and MPG suppressed oxidative stress by decreasing malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. The levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were ameliorated. Moreover, these flavonones enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and the expression of silent mating type information regulation 2 homolog 1 (SIRT1) and peroxisome proliferator-activated receptor α (PPARα), and reduced the expression of sterol regulatory element binding protein-1c (SREBP1c) and the downstream targets fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), and stearoyl-CoA desaturase 1 (SCD1). Molecular docking was used to predict the interaction and combination patterns between the three flavonones and the enzymes above. The results revealed that the SIRT1/AMPK pathway is involved in the functions of the three flavonones, and the most effective flavonone against hepatic steatosis might be PCBG, followed by MPG and PCB. Therefore, the three flavonones from P. chinense were found to exert preventive effects against hepatic steatosis by regulating the SIRT1/AMPK pathway.

Key Genes and Pathways Associated With Inner Ear Malformation in SOX10  p.R109W Mutation Pigs.

SRY-box 10 (SOX10) mutation may lead to inner ear deformities. However, its molecular mechanisms on inner ear development are not clear. In this work, the inner ear morphology was investigated at different embryonic stages of the SOX10 mutation miniature porcine model with sensorineural hearing loss, and high-throughput RNA-seq and bioinformatics analyses were applied. Our results indicated that the SOX10 mutation in the miniature pigs led to an incomplete partition (IP) of the cochlea, a cystic apex caused by fusion from middle and apical turns, cochlear modiolar defects and a shortened cochlear duct. The model demonstrated 173 differentially expressed genes (DEGs) and 185 differentially expressed long non-coding RNAs (lncRNAs). The down-regulated DEGs most significantly enriched the inflammatory mediator regulation of the TRP channels, arachidonic acid metabolism, and the salivary secretion pathways, while the up-regulated DEGs most significantly enriched the systemic lupus erythematosus and alcoholism pathways. Based on gene cluster analysis, we selected four gene groups: WNT1, KCNQ4, STRC and PAX6.

Inner ear structure of miniature pigs measured by multi-planar reconstruction techniques.

To study the structures of the scala vestibuli and tympani of miniature pigs in order to evaluate the feasibility of using miniature pigs as the animal model for cochlear implant. The temporal bones of three miniature pigs with normal hearing were scanned by micro-CT. With the aid of the Mimics software, we reconstructed the 3D structure of inner ear basing on the serial images of the miniature pig, and obtained dimensions of the scala vestibuli and tympani with multi-planar reconstruction (MPR) technique. The constructed slicing images displayed the fine structures of the cochlea. The results of our study showed that the cross-sectional areas of the scala tympani were greatest at 2.67 ± 0.90 mm2 when the circumferential length from the starting point of basal turn of the cochlea reached to 1.16 mm. The scala vestibuli has a largest width and height at the starting point of basal turn. The width and the height were 2.65 ± 0.45 mm and 2.43 ± 0.2 mm respectively. The largest width and height of the scala tympani were 2.17 ± 0.30 mm and 1.83 ± 0.42 mm. The result of our study suggests that the cochlea of miniature pigs is highly consistent with human's. Miniature pigs may be used as a new model for cochlear implant. MPR technique may be used as a new approach to obtain further information of patient's cochlea in surgeons which is helpful to select suitable cochlear implant devices and surgery approach.

The excited-state decay mechanism of 2,4-dithiothymine in the gas phase, microsolvated surroundings, and aqueous solution.

The photophysics of thiothymines has been extensively studied computationally in the past few years due to their significant potential as photosensitizers in photodynamic therapy. However, the corresponding computational studies of the photophysical mechanism of 2,4-dithiothymine are scarce. Herein we have employed the CASPT2//CASSCF and QM(CASPT2//CASSCF)/MM methods to systematically explore the excited-state decay mechanism of 2,4-dithiothymine in isolated, microsolvated, and aqueous surroundings. First, we have optimized minima and conical intersections in and between the lowest six excited singlet and triplet states i.e., , , , , and ; then, based on computed excited-state decay paths and spin-orbit couplings, we have proposed several nonadiabatic pathways that efficiently populate the lowest triplet state to explain the experimentally observed ultrahigh triplet-state quantum yield. Moreover, we have found that the excited-state decay mechanism in microsolvated and aqueous environments is more complicated than that in the gas phase. The solute-solvent interaction has significant effects on the excited-state potential energy surfaces of 2,4-dithiothymine and eventually on its excited-state decay mechanism. Finally, the present computational efforts contribute important mechanistic knowledge to the understanding of the photophysics of thiothymine-based photosensitizers.

Alkaloids from piper longum protect dopaminergic neurons against inflammation-mediated damage induced by intranigral injection of lipopolysaccharide.

BACKGROUND: Alkaloids from Piper longum (PLA), extracted from P. longum, have potent anti-inflammatory effects. The aim of this study was to investigate whether PLA could protect dopaminergic neurons against inflammation-mediated damage by inhibiting microglial activation using a lipopolysaccharide (LPS)-induced dopaminergic neuronal damage rat model. METHODS: The animal behaviors of rotational behavior, rotarod test and open-field test were investigated. The survival ratio of dopaminergic neurons and microglial activation were examined. The dopamine (DA) and its metabolite were detected by high performance liquid chromatography (HPLC). The effects of PLA on the expression of interleukin (IL)-6, interleukin (IL)-1ß and tumor necrosis factor (TNF)-α were detected by enzyme-linked immunosorbent assay (ELISA). Reactive oxygen species (ROS) and nitric oxide (NO) were also estimated. RESULTS: We showed that the survival ratio of tyrosine hydroxylase-immunoreactive (TH-ir) neurons in the substantia nigra pars compacta (SNpc) and DA content in the striatum were reduced after a single intranigral dose of LPS (10 µg) treatment. The survival rate of TH-ir neurons in the SNpc and DA levels in the striatum were significantly improved after treatment with PLA for 6 weeks. The over-activated microglial cells were suppressed by PLA treatment. We also observed that the levels of inflammatory cytokines, including TNF-α, IL-6 and IL-1ß were decreased and the excessive production of ROS and NO were abolished after PLA treatment. Therefore, the behavioral dysfunctions induced by LPS were improved after PLA treatment. CONCLUSION: This study suggests that PLA plays a significant role in protecting dopaminergic neurons against inflammatory reaction induced damage.

[Protective effect of alkaloids from Piper longum in rat dopaminergic neuron injury of 6-OHDA-induced Parkinson's disease].

OBJECTIVE: To discuss the protective effect of alkaloids from Piper longum (PLA) in rat dopaminergic neuron injury of 6-OHDA-induced Parkinson's disease and its possible mechanism. METHOD: The rat PD model was established by injecting 6-OHDA into the unilateral striatum with a brain solid positioner. The PD rats were divided into the PLA group (50 mg x kg(-1) x d(-1)), the madorpa group (50 mg x kg(-1) x d(-1)) and the model group, with 15 rats in each group. All of the rats were orally given drugs once a day for 6 weeks. Meanwhile, other 15 rats were randomly selected as the sham operation group, and only injected with normal saline in the unilateral striatum. The behavioral changes were observed with the apomorphine (APO)-induced rotation and rotary rod tests. The number of tyrosine hydroxylase (TH)-positive cells in rat substantia nigra and the density of TH-positive fibers in striatum were detected by tyrosine hydroxylase immunohistochemistry. The content of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione (GSH), catalase (CAT), malondialdehyde (MDA), nitric oxide (NO) and nitric oxide synthase (NOS) in rat substantia nigra and striatum were measured by the spectrophotometric method. RESULT: After being induced by APO, PD rats showed obvious rotation behaviors, with decreased time stay on rotary rod and significant reduction in the number of TH-positive cells in sustantia nigra and the density of TH-positive fibers in striatum. The activities of SOD, GSH-Px, CAT, the content of GSH and the total antioxidant capacity significantly decreased, whereas the activities of NOS and the content of MDA, NO significantly increased. PLA could significantly improve the behavioral abnormality of PD rats and increase the number of TH-positive cells in sustantia nigra and the density of TH-positive fibers in striatum. It could up-regulate the activities of SOD, GSH-Px, CAT, the content of GSH and the total antioxidant capacity, and decrease the content of NOS and the content of MDA, NO. CONCLUSION: Alkaloids from P. longum shows the protective effect in substantia nigra cells of 6-OHDA-induced PD model rats. Its mechanism may be related with their antioxidant activity.

[Math1 gene therapy for kanamycin and furosemide-induced deaf guinea pigs].

OBJECTIVE: To observe the morphology and function changes of cochlear hair cells before and after math1 gene injection into the cochlea of deaf guinea pigs which were induced by kanamycin and furosemide. To explore the feasibility of Math1 gene for medicine-induced deafness therapy. METHODS: Kanamycin (500 mg/kg) and furosemide (50 mg/kg) were given to the healthy adult guinea pigs intramuscularly and intravenously to establish the deafness model. The guinea pigs whose auditory brainstem response (ABR) threshold > 95 dB SPL were randomly divided into five groups. Blank control group (without any treatment, n = 3), operation control group (right ear scala tympani operation, n = 3), artificial perilymph group (right ear scala tympani injection artificial perilymph, n = 3), virus vector group [right ear scala tympani injection adenovirus which carrying enhanced green fluorescent protein (EGFP) gene (Ad. EGFP) , n = 4], Math1 gene therapy group [right ear scala tympani injection adenovirus which carrying Math1 and EGFP gene (Ad. Math1-EGFP), n = 6]. Each animal received ABR test before and after injection. The cochlear tissue was observed by scanning electronic microscopy. RESULTS: The ABR thresholds of tone burst( 4, 8, 16, 20 kHz ) were not statistically significant in different groups (P > 0.05). The number of hair cells increased in some of severe deaf guinea pigs after the injection of Ad. Math1-EGFP gene. However, there was no obvious difference with morphology and numbers of cochlea hair cells in other groups. CONCLUSIONS: The injection of Math1 gene to cochlea can regenerate or repair the hair cells of medicine-induced deaf guinea pigs, but there was no improvement on the hearing loss.

[Epidemiological study of cytopenia among benzene-exposed workers and its influential factors].

OBJECTIVE: To evaluate the benzene exposure level and cytopenia among the benzene exposed workers in Shanghai, China and to analyze the influential factors for the health of benzene-exposed workers. METHODS: A total of 3314 benzene-exposed workers, who were from 85 benzene-related enterprises selected by stratified random sampling based on enterprise sizes and industries, were included in the study. The time-weighted average (TWA) concentration of benzene in each workshop was measured by individual sampling and fixed point sampling, and the benzene exposure level in workshop was evaluated accordingly. The occupational health examination results and health status of benzene-exposed workers were collected. RESULTS: The median of TW A concentrations of benzene was 0.3 mg/m3. The TWA concentrations measured at 7 ( 1.4%) of the 504 sampling points were above the safety limit. Of the 7 points, 3 were from large enterprises, 2 from medium enterprises, and 2 from small enterprises; 3 were from shipbuilding industry, 1 from chemical industry, and 3 from light industry. Of the 3314 benzene-exposed workers, 451 ( 13.6%) had cytopenia, including 339 males ( 339/2548, 13.3%) and 112 females ( 112/766, 14.6% ). There were significant differences in the incidence rates of leukopenia and neutropenia among the benzene-exposed workers of different sexes and ages (P<0.05); there were significant differences in the incidence rate of cytopenia among the benzene-exposed workers of different ages and working years ( P<0.05 ); there were significant differences in the incidence of neutropenia among the benzene exposed workers of different working years ( P<0.05). CONCLUSION: Monitoring and intervention measures should be enhanced to protect the benzene-exposed workers in the large enterprises in shipbuilding industry and medium and private enterprises in chemical industry from occupational hazards.

[Comparative study on the treatment of acromioclavicular joint dislocation: coracoclavicular ligament reconstruction combined with hook plate fixation or suture-anchor fixation].

OBJECTIVE: To investigate the clinical outcomes of acromioclavicula (AC) joint dislocation treated with coracoclavicular (CC) ligament reconstruction and hook plate fixation/suture-anchor fixation. METHODS: There were 105 patients with Rockwood type III or severer AC joint dislocations were randomly divided into two groups from February 2007 to April 2010. They were treated with CC ligament reconstruction using double bundle of Palmaris longus (hook plate fixation group, 54 cases), and subsequently fixed with hook plates or suture-anchors (suture-anchors group, 51 cases). Patients were followed up, and the AC distance and CC distance were measured on the postoperative X-ray films, and the outcomes were assessed according to Karlsson criteria and Constant-Murley shoulder score. Ranked data was analyzed with the use of χ(2) test and measurement data with two sample t test. RESULTS: Eighty-nine patients were followed up for 24-42 months, average 30 months. There were 46 cases in hook plate fixation group and 43 cases in suture-anchor fixation group, without significant difference in age, gender, injured side and Rockwood classification between both groups. Between the two groups, no statistical difference was detected in the AC and CC distance measured within 6 months after operation (P > 0.05). The AC and CC distances of hook plate fixation group measured in 24 months postoperatively were larger than those in suture-anchor fixation group, respectively (F = 1.904 and 1.854, P < 0.05). In hook plate fixation group, the AC and CC distances measured in 24 months postoperatively were larger than those measured in 6 month postoperatively, respectively (F = 1.863 and 1.842, P < 0.05). According to Constant-Murley shoulder score, the average score was 88.5 for hook plate fixation group and 92.7 for suture-anchor fixation group (F = 0.475, P = 0.017). According to Karlsson criteria, the excellent and good rate of the functional recovery was 95.4% in suture-anchor fixation group, better than hook plate fixation group (χ(2) = 4.564, P = 0.033). CONCLUSIONS: The clinical outcomes of AC joint dislocation treated with CC ligament reconstruction and suture-anchor fixation are better than those treated with CC ligament reconstruction and hook plate fixation. The AC and CC distances increase after the removal of hook plate, which may be associated with poor functional recovery.

Modulation of Mcl-1 expression reduces age-related cochlear degeneration.

Mcl-1 is an anti-apoptotic member of the Bcl-2 family that modulates apoptosis-related signaling pathways and promotes cell survival. We have previously demonstrated a reduction of Mcl-1 expression in aging cochleae. To investigate whether restoring Mcl-1 expression would reduce aging-related cochlear degeneration, we developed a rat model of Mcl-1 overexpression. A plasmid encoding human Mcl-1/enhanced green fluorescent protein was applied to the round window of the cochlea. This in vivo treatment transfected both the sensory and supporting cells of the cochlear sensory epithelium and enhanced Mcl-1 expression at both the mRNA and the protein level. The upregulation of Mcl-1 expression reduced the progression of age-related cochlear dysfunction and sensory cell death. Furthermore, the transfection of Mcl-1 exerted its protective effect by suppressing cochlear apoptosis at the mitochondrial level. This study demonstrates that the genetic modulation of Mcl-1 expression reduces the progression of age-related cochlear degeneration.

Migration and differentiation of mouse embryonic stem cells transplanted into mature cochlea of rats with aminoglycoside-induced hearing loss.

CONCLUSION: Mouse embryonic stem cells (ESCs) transplanted into the scala tympani are able to migrate in the cochlea of rats deafened with aminoglycoside and partly restore the structure of sensory epithelia of the inner ear. OBJECTIVES: To explore the migration and differentiation of enhanced green fluorescence protein (EGFP)-expressing ESCs by transplanting them into the scala tympani of rats with amikacin sulfate-induced hearing loss. METHODS: Adult Sprague-Dawley (SD) rats were deafened with amikacin sulfate. Mouse ESCs expressing EGFP (EGFP-ESCs) were transplanted into the scala tympani. The migration and differentiation were observed at different time points. RESULTS: EGFP-ESCs transplanted into normal cochlea did not migrate, but those in the amikacin-damaged cochlea could survive and migrate into the scala media and the vestibular cisterna. For the first time, we observed that the EGFP-ESCs migrated into the scala media, took the place of the organ of Corti, and formed a structure just like the cochlear tunnel. Some grafted stem cells even expressed myosin VIIa, the molecular marker of hair cells. Some nerve fibers reached to the bottom of the hair cell-like cells. The ESCs migrated into the vestibule and restored the sensory epithelia of the ampullary crest. The number of the transplanted ESCs reduced over the 6 week period of the study.

Regeneration of stereocilia of hair cells by forced Atoh1 expression in the adult mammalian cochlea.

The hallmark of mechanosensory hair cells is the stereocilia, where mechanical stimuli are converted into electrical signals. These delicate stereocilia are susceptible to acoustic trauma and ototoxic drugs. While hair cells in lower vertebrates and the mammalian vestibular system can spontaneously regenerate lost stereocilia, mammalian cochlear hair cells no longer retain this capability. We explored the possibility of regenerating stereocilia in the noise-deafened guinea pig cochlea by cochlear inoculation of a viral vector carrying Atoh1, a gene critical for hair cell differentiation. Exposure to simulated gunfire resulted in a 60-70 dB hearing loss and extensive damage and loss of stereocilia bundles of both inner and outer hair cells along the entire cochlear length. However, most injured hair cells remained in the organ of Corti for up to 10 days after the trauma. A viral vector carrying an EGFP-labeled Atoh1 gene was inoculated into the cochlea through the round window on the seventh day after noise exposure. Auditory brainstem response measured one month after inoculation showed that hearing thresholds were substantially improved. Scanning electron microscopy revealed that the damaged/lost stereocilia bundles were repaired or regenerated after Atoh1 treatment, suggesting that Atoh1 was able to induce repair/regeneration of the damaged or lost stereocilia. Therefore, our studies revealed a new role of Atoh1 as a gene critical for promoting repair/regeneration of stereocilia and maintaining injured hair cells in the adult mammal cochlea. Atoh1-based gene therapy, therefore, has the potential to treat noise-induced hearing loss if the treatment is carried out before hair cells die.

[Expression of homeobox A9 in myeloid leukemia cell line HL-60 and effect of drugs on its expression].

This study was aimed to investigate the homeobox A9 (HOXA9) mRNA and protein expression in myeloid leukemia cell line HL-60 and effect of all-trans retinoic acid (ATRA 1 µmol/L) or arsenic trioxide (As2O3 1 µmol/L) on its expression, and to explore the pathogenesis of leukemia mediated by HOXA9 at mRNA and protein levels. The expression of HOXA9 mRNA and protein were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction (FQ-RT-PCR) and Western blot, respectively. HL-60 cells were divided into 3 group: normal control added with RPMI 1640 medium, ATRA group and As2O3 group. The results indicated that HOXA9 mRNA expression in each group showed a firstly increasing and then decreasing tendency, in which the expression of HOXA9 mRNA was observed at day 1, increased at day 2, and decreased at day 3; while HOXA9 protein expression in each group was observed at day 1, the expression of HOXA9 protein in control group and ATRA group showed firstly increase and then decrease. The expression of HOXA9 protein in As2O3 group showed a decreased tendency gradually. The expression of HOXA9 mRNA in ATRA groups at day 1-3 was higher than that in control group (P < 0.05). The differences of HOXA9 mRNA expression between As2O3 groups and the control group were not significant at day 1 and day 3, but was higher than that in control group at day 2 (P < 0.05). The expression of HOXA9 protein in ATRA group at day 1- day 3 was higher than that in control group (P < 0.05). Compared with control group, the expression of HOXA9 protein in As2O3 group was higher at day 1 (P < 0.05), lower at day 2 (P < 0.05), and no significant differences at day 3. It is concluded that HOXA9 mRNA and protein express in HL-60 cells. ATRA 1 µmol/L can up-regulate the expression of HOXA9 mRNA and protein in HL-60 cells. The mechanisms of treatment of leukemia by ATRA and As2O3 may be associated with the regulation of the HOXA9 mRNA or protein expression.