Simplified methodology for large scale isolation of homozygous transgenic lines of lettuce

Background: Lettuce is a globally important leafy vegetable and a model plant for biotechnology due to its adaptability to tissue culture and stable genetic transformation. Lettuce is also crucial for functional genomics research in the Asteraceae which includes species of great agronomical importance. The development of transgenic events implies the production of a large number of shoots that must be differentiated between transgenic and non-transgenic through the activity of the selective agent, being kanamycin the most popular. Results: In this work we adjusted the selection conditions of transgenic seedlings to avoid any escapes, finding that threshold concentration of kanamycin was 75 mg/L. To monitor the selection system, we studied the morphological response of transgenic and non-transgenic seedlings in presence of kanamycin to look for a visual morphological marker. Several traits like shoot length, primary root length, number of leaves, fresh weight, and appearance of the aerial part and development of lateral roots were affected in non-transgenic seedlings after 30 d of culture in selective media. However, only lateral root development showed an early, qualitative and reliable association with nptII presence, as corroborated by PCR detection. Applied in successive transgenic progenies, this method of selection combined with morphological follow-up allowed selecting the homozygous presence of nptII gene in 100% of the analyzed plants from T2 to T5. Conclusions: This protocol allows a simplified scaling-up of the production of multiple homozygous transgenic progeny lines in the early generations avoiding expensive and time-consuming molecular assays.

Determining Genotypic Drug Resistance by Ion Semiconductor Sequencing With the Ion AmpliSeq™ TB Panel in Multidrug-Resistant Mycobacterium tuberculosis Isolates

BACKGROUND: We examined the feasibility of a full-length gene analysis for the drug resistance-related genes inhA, katG, rpoB, pncA, rpsL, embB, eis, and gyrA using ion semiconductor next-generation sequencing (NGS) and compared the results with those obtained from conventional phenotypic drug susceptibility testing (DST) in multidrug-resistant Mycobacterium tuberculosis (MDR-TB) isolates. METHODS: We extracted genomic DNA from 30 pure MDR-TB isolates with antibiotic susceptibility profiles confirmed by phenotypic DST for isoniazid (INH), rifampin (RIF), ethambutol (EMB), pyrazinamide (PZA), amikacin (AMK), kanamycin (KM), streptomycin (SM), and fluoroquinolones (FQs) including ofloxacin, moxifloxacin, and levofloxacin. Enriched ion spheres were loaded onto Ion PI Chip v3, with 30 samples on a chip per sequencing run, and Ion Torrent sequencing was conducted using the Ion AmpliSeq TB panel (Life Technologies, USA). RESULTS: The genotypic DST results revealed good agreement with the phenotypic DST results for EMB (Kappa 0.8), PZA (0.734), SM (0.769), and FQ (0.783). Agreements for INH, RIF, and AMK+KM were not estimated because all isolates were phenotypically resistant to INH and RIF, and all isolates were phenotypically and genotypically susceptible to AMK+KM. Moreover, 17 novel variants were identified: six (p.Gly169Ser, p.Ala256Thr, p.Ser383Pro, p.Gln439Arg, p.Tyr597Cys, p.Thr625Ala) in katG, one (p.Tyr113Phe) in inhA, five (p.Val170Phe, p.Thr400Ala, p.Met434Val, p.Glu812Gly, p.Phe971Leu) in rpoB, two (p.Tyr319Asp and p.His1002Arg) in embB, and three (p.Cys14Gly, p.Asp63Ala, p.Gly162Ser) in pncA. CONCLUSIONS: Ion semiconductor NGS could detect reported and novel amino acid changes in full coding regions of eight drug resistance-related genes. However, genotypic DST should be complemented and validated by phenotypic DSTs.

Improvement of clavulanic acid production in Streptomyces clavuligerus F613-1 by using a claR-neo reporter strategy

Background: Streptomyces clavuligerus was the producer of clavulanic acid, claR, a pathway-specific transcriptional regulator in S. clavuligerus, positively regulates clavulanic acid biosynthesis. In this study, the promoter-less kanamycin resistance gene neo was fused with claR to obtain strain NEO from S. clavuligerus F613-1. The claR-neo fusion strain NEO was mutated using physical and chemical mutagens and then screened under high concentrations of kanamycin for high-yield producers of clavulanic acid. Results: The reporter gene neo was fused downstream of claR and used as an indicator for expression levels of claR in strain NEO. After three rounds of continuous treatment and screening, the high-yield clavulanic acid-producing strain M3-19 was obtained. In the shaking flask model, the clavulanic acid titer of M3-19 reached 4.33 g/L, which is an increase of 33% over the titer of 3.26 g/L for the starting strains S. clavuligerus F613-1 and NEO. Conclusions: Our results indicate that neo can be effectively used as a reporter for the expression of late-stage biosynthetic genes when screening for high-yield strains and that this approach has strong potential for improving Streptomyces strains of industrial value.

DRESS (drug reaction with eosinophilia and systemic symptom) syndrome caused by both first-line and second-line antitubercular medications: A case report with a brief literature review

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare but potentially fatal drug-induced systemic hypersensitivity response characterized by erythematous eruption, fever, leukocytosis with eosinophilia, and internal organ involvement. Antitubercular agents are potential causative agents for DRESS syndrome but difficult to verify as a culprit drug, since antitubercular agents are coadministered as a combination regimen. A 42-year-old female with endobronchial tuberculosis was diagnosed with DRESS syndrome after 4-week treatment of isoniazid, rifampicin, ethambutol, and pyrazinamide with prednisolone 50 mg. All the antitubercular agents were stopped and replaced with levofloxacin, cycloserine, p-aminosalicylic acid, and kanamycin. However, severe exacerbation of DRESS syndrome compelled the patient to discontinue the administration of the second-line antitubercular agents. Two months later, the patient underwent a patch test for all the antitubercular agents which had been used, and the results showed positivity to isoniazid and cycloserine. We report a rare case of DRESS syndrome that reacted to cycloserine as well as isoniazid. Development of coreactivity to other drugs should be differentiated with a flare-up reaction in the management of DRESS syndrome.

Antibiotic resistance patterns and genetic relatedness of Enterococcus faecalis and Enterococcus faecium isolated from military working dogs in Korea

Enterococcus spp. are normally present in the gastrointestinal tracts of animals and humans, but can cause opportunistic infections that can be transmitted to other animals or humans with integrated antibiotic resistance. To investigate if this is a potential risk in military working dogs (MWDs), we analyzed antibiotic resistance patterns and genetic relatedness of Enterococcus spp. isolated from fecal samples of MWDs of four different age groups. Isolation rates of Enterococcus spp., Enterococcus (E.) faecalis, and E. faecium, were 87.7% (57/65), 59.6% (34/57), and 56.1% (32/57), respectively, as determined by bacterial culture and multiplex PCR. The isolation rate of E. faecalis gradually decreased with age (puppy, 100%; adolescent, 91.7%; adult, 36.4%; and senior, 14.3%). Rates of resistance to the antibiotics ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole/trimethoprim, imipenem, and kanamycin among Enterococcus spp. increased in adolescents and adults and decreased in senior dogs, with some isolates having three different antibiotic resistance patterns. There were indistinguishable pulsed-field gel electrophoresis patterns among the age groups. The results suggest that Enterococcus is horizontally transferred, regardless of age. As such, periodic surveillance studies should be undertaken to monitor changes in antibiotic resistance, which may necessitate modification of antibiotic regimens to manage antibiotic resistance transmission.

A Case of Disseminated Multidrug-Resistant Tuberculosis involving the Brain / 감염과화학요법

We report a case of a 23-year-old female immigrant from China who was diagnosed with multidrug-resistant tuberculosis affecting her lung and brain, resistant to the standard first-line therapeutics and streptomycin. She was treated with prothionamide, moxifloxacin, cycloserine, and kanamycin. However, her headache and brain lesion worsened. After the brain biopsy, the patient was confirmed with intracranial tuberculoma. Linezolid was added to intensify the treatment regimen, and steroid was added for the possibility of paradoxical response. Kanamycin was discontinued 6 months after initiation of the treatment; she was treated for 18 months with susceptible drugs and completely recovered. To our knowledge, this case is the first multidrug-resistant tuberculosis that disseminated to the brain in Korea.

Diagnosis and Treatment of Multidrug-Resistant Tuberculosis / 대한내과학회지

Despite global efforts to control tuberculosis (TB), multidrug-resistant TB (MDR-TB) is still a serious problem worldwide. The diagnosis of MDR-TB is based on mycobacterial culture followed by drug susceptibility testing, with results available in weeks to months. This requirement calls for rapid direct tests, especially genotypic tests, in which specimens are amplified directly for the detection of MDR-TB. The treatment of MDR-TB is challenging because of the high toxicity of second-line drugs and the longer treatment duration required compared to drug-susceptible TB. The selection of drugs in MDR-TB is based on the treatment history, drug susceptibility results, and TB drug resistance patterns in each region. Recent World Health Organization guidelines recommend the use of at least four second-line drugs (i.e., a newer fluoroquinolone, an injectable agent, prothionamide, and cycloserine or para-aminosalicylic acid) in addition to pyrazinamide. Kanamycin is the initial choice of an injectable drug, and newer fluoroquinolones include levofloxacin and moxifloxacin. For extensively drug-resistant TB, group 5 drugs such as linezolid and clofazimine need to be included. New drugs such as delamanid and bedaquiline have recently been approved for treating MDR-TB and other agents with novel mechanisms of action that can be given for shorter durations (6-12 months) for MDR-TB are under investigation.

Successful readministration of second-line antituberculous agents in a patient with near-fatal drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome

For the treatment of multidrug-resistant (MDR) tuberculosis, maintenance of appropriate antituberculous agents is essential because of its low cure rate and high dropout rate. Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe drug-induced systemic hypersensitivity response resulting in cessation of causative agents. In cases of second-line antituberculous agent-induced DRESS, it is extremely difficult to find other replacement medications to cure MDR tuberculosis. A 53-year-old male who had taken the second-line antituberculous agents (cycloserine, streptomycin, p-aminosalicylic acid, and prothionamide) as well as pyrazinamide for 5 weeks experienced DRESS syndrome accompanying hepatic coma. His symptoms improved with discontinuation of antituberculous agents and administration of high-dose methylprednisolone for 1 month. To resume the antituberculous medication, second-line antituberculous agents were administered one by one using a rapid desensitization protocol. While kanamycin, levofloxacin, and cycloserine were successfully readministered, p-aminosalicylic acid- and prothionamide-induced cutaneous hypersensitivity symptoms were relatively mild compared to previous reactions. Herein, we report a case of successfully treated MDR tuberculosis having a history of fatal DRESS syndrome to antituberculous agents using the rapid desensitization protocol.

The spiral ganglion degeneration and the expression of EFR3A in the cochlea of the deaf mice induced by co-administration of kanamycin and furosemide / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the spiral ganglion degeneration and the expression of EFR3A in the cochlea of the deaf mice induced by co-administration of kanamycin and furosemide.</p><p><b>METHODS</b>Eight weeks old C57BL/6J mice were administered with a single dose of kanamycin followed by furosemide, then fluorescent immunohistochemistry staining and transmission electron microscopy were applied to observe the SGNs' degeneration process and extent characteristics at 1, 5, 15, 30 and 60 days following treatment. We detected the expression of EFR3A during the degeneration of SGNs via fluorescent immunohistochemistry and western blotting.</p><p><b>RESULTS</b>Co-administration of kanamycin and furosemide quickly induced cochlear hair cell death in mice, and then caused progressive degeneration of SGNs. Our results showed that the abnormal morphology of SGNs occurredat day 5 following administration, and the number of SGNs began to decrease at day 15. Compared to the control group, it was found the remarkable increase of the EFR3A protein at the fifth day after co-administration, then decreased to the nearly normal at 15 days following treatment, and no further significant changes thereafter.</p><p><b>CONCLUSION</b>The changes of the EFR3A protein expression in the spiral ganglion of the cochlea in mice are coincidence with the time of the SGNs degeneration to happen, which imply that EFR3A may play an important role in the occurrence of the SGNs' degeneration in the cochlea in mice following hair cells loss.</p>

Math1 gene therapy for kanamycin and furosemide-induced deaf guinea pigs / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Medical Treatment of Pulmonary Multidrug-Resistant Tuberculosis / 감염과화학요법

Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging because of the high toxicity of second-line drugs and the longer treatment duration required compared with drug-susceptible TB. The efficacy of treatment for MDR-TB is poorer than that for drug-susceptible TB. The selection of drugs in MDR-TB is based on previous treatment history, drug susceptibility results, and TB drug resistance patterns in the each region. Recent World Health Organization guidelines recommend the use of least 4 second-line drugs (a newer fluoroquinolone, an injectable agent, prothionamide, and cycloserine or para-aminosalicylic acid) in addition to pyrazinamide. The kanamycin is the initial choice of injectable durgs, and newer fluoroquinolones include levofloxacin and moxifloxacin. For MDR-TB, especially cases that are extensively drug-resistant, group 5 drugs such as linezolid, clofazimine, and amoxicillin/clavulanate need to be included. New agents with novel mechanisms of action that can be given for shorter durations (9-12 months) for MDR-TB are under investigation.

Evaluation of Reverse Hybridization Assay for Detecting Fluoroquinolone and Kanamycin Resistance in Multidrug-Resistance Mycobacterium tuberculosis Clinical Isolates / 결핵및호흡기질환

BACKGROUND: Multidrug-resistant tuberculosis (MDR-TB) is an increasing public health problem and poses a serious threat to global TB control. Fluoroquinolone (FQ) and aminoglycoside (AG) are essential anti-TB drugs for MDR-TB treatment. REBA MTB-FQ(R) and REBA MTB-KM(R) (M&D, Wonju, Korea) were evaluated for rapid detection of FQ and kanamycin (KM) resistance in MDR-TB clinical isolates. METHODS: M. tuberculosis (n=67) were isolated and cultured from the sputum samples of MDR-TB patients for extracting DNA of the bacilli. Mutations in genes, gyrA and rrs, that have been known to be associated with resistance to FQ and KM were analyzed using both REBA MTB-FQ(R) and REBA MTB-KM(R), respectively. The isolates were also utilized for a conventional phenotypic drug susceptibility test (DST) as the gold standard of FQ and KM resistance. The molecular and phenotypic DST results were compared. RESULTS: Sensitivity and specificity of REBA MTB-FQ(R) were 77 and 100%, respectively. Positive predictive value and negative predictive value of the assay were 100 and 95%, respectively, for FQ resistance. Sensitivity, specificity, positive predictive value and negative predictive value of REBA MTB-KM(R) for detecting KM resistance were 66%, 94%, 70%, and 95%, respectively. CONCLUSION: REBA MTB-FQ(R) and REBA MTB-KM(R) evaluated in this study showed excellent specificities as 100 and 94%, respectively. However, sensitivities of the assays were low. It is essential to increase sensitivity of the rapid drug resistance assays for appropriate MDR-TB treatment, suggesting further investigation to detect new or other mutation sites of the associated genes in M. tuberculosis is required.

Serotype and antimicrobial susceptibility of Actinobacillus pleuropneumoniae isolates from pigs in Korea / 대한수의학회지

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.

Research progress of acute kanamycin sulfate-induced deafness in guinea pig / 临床耳鼻咽喉头颈外科杂志

To present a summary of current knowledge regarding acute kanamycin sulfate-induced deafness in guinea pig, by reviewing the published literature. Animal model of acute deafness induced by a single dose of kanamycin sulfate in combination with ethacrynic acid or furosemide in guinea pig was usually used to investigate the mechanism of cochlear cell degeneration. There were different time sequences of cell degeneration of spiral ganglion cell and hair cell in different studies. The findings may result from different doses, order of two drugs administration or time point chosen. There remains scope for further research in chronic kanamycin-induced deafness, which more replicates the type of exposure to people than acute deafness.

Decreased Immunoreactivities of the Chloride Transporters, KCC2 and NKCC1, in the Lateral Superior Olive Neurons of Kanamycin-treated Rats

OBJECTIVES: From our previous study about the weak expressions of potassium-chloride (KCC2) and sodium-potassium-2 chloride (NKCC1) co-transporters in the lateral superior olive (LSO) in circling mice, we hypothesized that partially damaged cochlea of circling mice might be a cause of the weak expressions of KCC2 or NKCC1. To test this possibility, we reproduced the altered expressions of KCC2 and NKCC1 in the LSO of rats, whose cochleae were partially destroyed with kanamycin. METHODS: Rat pups were treated with kanamycin from postnatal (P)3 to P8 (700 mg/kg, subcutaneous injection, twice a day) and sacrificed for immunohistochemical analysis, scanning electron microscope (SEM) and auditory brain stem response. RESULTS: The SEM study revealed partially missing hair cells in P9 rats treated with kanamycin, and the hearing threshold was elevated to 63.8+/-2.5 dB SPL (4 ears) at P16. Both KCC2 and NKCC1 immunoreactivities were more prominent in control rats on P16. On 9 paired slices, the mean densities of NKCC1 immunoreactivities were 118.0+/-1.0 (control) and 112.2+/-1.2 (kanamycin treated), whereas those of KCC2 were 115.7+/-1.5 (control) and 112.0+/-0.8 (kanamycin treated). CONCLUSION: We concluded that weak expressions of KCC2 and NKCC1 in circling mice were due to partial destruction of cochleae.

Pharmacokinetics of amikacin in plasma of healthy goats after intravenous injection once daily for three days / 대한수의학회지

Amikacin is a semisynthetic derivative of kanamycin and primarily active against aerobic Gram-negative-pathogens with limited activity against Gram-positive bacteria. Meager study was reported on pharmacokinetic data on multi-days administration of amikacin. Hence, pharmacokinetics study was done in five clinically healthy goats (n = 5), after intravenous bolus injection of amikacin sulfate at the dose rate of 10 mg/kg body weight daily for three consecutive days. The amikacin concentrations in plasma and pharmacokinetics-parameters were analyzed by using microbiological assay technique and noncompartmental open-model, respectively. The mean peak plasma concentrations (Mean +/- SD) of amikacin at time zero (Cp0) was 114.19 +/- 20.78 and 128.67 +/- 14.37 microg/mL, on day 1st and 3rd, respectively. The mean elimination half-life (t(1/2)ke) was 1.00 +/- 0.28 h on day 1st and 1.22 +/- 0.29 h on day 3rd. Mean of area under concentration-time curve (AUC(0-->infinity)) was 158.26 +/- 60.10 and 159.70 +/- 22.74 microg.h/mL, on day 1st and 3rd respectively. The total body clearance (ClB) and volume of distribution at steady state (Vdss) on day 1st and 3rd were ClB = 0.07 +/- 0.02 and 0.06 +/- 0.01 L/h.kg and Vdss = 0.10 +/- 0.03 and 0.11 +/- 0.05 L/kg, respectively. No-significant difference was noted in both drug-plasma concentration and pharmacokinetics-parameters, respectively. Amikacin concentration in plasma was found higher up-to 4 h and 6 h onward on down-ward trends favour to reduce toxicity. Which also support the pharmacokinetic-pharmacodynamic way of dosing of aminoglycosides and hence, amikacin may be administered 10 mg/kg intravenously daily to treat principally Gram-negative pathogens and limitedly Gram-positive-pathogens.

Ototoxicity of kanamycin sulfate in adult rats and its underlying mechanisms / 生理学报

The aim of the present study was to assess the ototoxicity of kanamycin sulfate (KM) in adult rats and its underlying mechanism. Forty male Sprague-Dawley rats (6-7 weeks old) were randomly divided into the experimental group and the control group. The animals in the experimental group were injected subcutaneously with KM (500 mg/kg per day) for two weeks, and the control group received equal volume of normal saline. To assess the ototoxicity of KM, the auditory brainstem response (ABR) was recorded to monitor the changes in hearing thresholds, and the density of spiral ganglion cells (SGCs) and morphology of cochlea were observed using surface preparations and frozen sections of cochlea. The results showed that the hearing threshold of rats in the experimental group was elevated by more than 60 dB across all the frequencies two weeks after the first administration of KM. And in the experimental group, the density of SGCs became lower, and organ of Corti suffered loss of hair cells. The loss of outer hair cells (OHCs) was more severe than that of inner hair cells (IHCs), correlated with the density decrease of SGCs. We conclude that the ototoxicity of KM in the adult rats was apparent and the underlying mechanism is associated with the loss of SGCs and hair cells.

Expression of TMPRSS3 in the rat cochlea following kanamycin ototoxicity / 中南大学学报(医学版)

OBJECTIVE@#To establish the kanamycin-induced deafness model in SD rats, and to investigate the expression and significance of transmembrane protease, serine 3 (TMPRSS3) in the cochlea following kanamycin ototoxicity.@*METHODS@#A total of 40 male SD rats were randomly divided into 4 groups. The experimental rats received intramuscular kanamycin sulfate for 3, 7, and 14 consecutive days, and the control group were treated with normal saline for 14 days. Auditory brainstem responses (ABR) were obtained before and after the kanamycin administration. The expression of TMPRSS3 in the cochlea was identified and detected by immunohistochemistry and Western blot.@*RESULTS@#Kanamycin-induced deafness model in the SD rats was successfully established. ABR thresholds were increased and the expression of TMPRSS3 in the cochlea was reduced after the kanamycin injection (P<0.01).@*CONCLUSION@#TMPRSS3 may play an important role in normal cochlea function and involve in the process of aminoglycoside antibiotics induced deafness.

The Effect of Ginkgo Biloba on the Survival of Spiral Ganglion Neurons in Rats / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Ginkgo biloba extract (GBE) enhances cell survival in various organs. GBE protects nerve cells in the central nervous system and is clinically applied in Parkinson's and Alzheimer's disease. GBE can protect ototoxicity caused by cisplantin and gentamycin through rescue of hair cells in Organ of Corti and is accepted as one of the therapeutic agents for sudden deafness and tinnitus. The experimental study on GBE for the inner ear is confined to the hair cells, not to the spiral ganglion neurons (SGNs) which is the stimulated part by the electrode of cochlear implant. The aim of this study is to elucidate the effect of GBE on the survival of SGNs after hair cell loss in rats. MATERIALS AND METHOD: Ten Sprague-Dawley rats aged 50 days (P50) were deafened with kanamycin sulfate. GBE (EGb 761) was injected into the right cochlea and artificial perilymph was injected into the left side. The number and size of SGNs were compared after immunohistochemical statin in both groups. The expression of pJun, which is well-known as a proapoptotic transcription factor in the cochlea, was also compared. RESULTS: The number of SGNs was significantly larger in the GBE group than the control. The expression of pJun activity was significantly decreased in GBE group than the control. The size of SGNs in both groups was similar. CONCLUSION: These results suggest that GBE can protect SGNs death by inhibiting the pJun-C-jun N-terminal kinase pathway. GBE might be a potential drug for the patients with total deafness before or after cochlear implantation surgery for better hearing results.