Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice. Methods Male C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice we...Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice. Methods Male C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice were randomly sclccted to be studied immediately after exposure （Group P0）, or 1 day （Group P1）, 3 days （Group P3）, 7 day （Group P7） or 14 days （P14） after exposure. Their before exposure condition served as the normal control. All mice were exposed to a broad-band white noise at 100 dB SPL for 2 hours, ABR thresholds were used to estimate hearing status at each time point. Results ABR threshold elevation was seen at every tested frequency at P0 （P〈0.01）. Elevation at high-frequencies （16 kHz and 32 kHz） was greater than at lower frequencies （4 kHz and 8 kHz, P〈0.05）. From P1 to P14, ABR thresholds continuously improved, and there was no significant difference between P14 and before exposure （P〉0.05）. Conclusion There is a frequency specific re- sponse to 100 dB SPL broad-band white noise in C57BL/6J mice, with the high-frequency being more susceptible. Hearing loss induced by moderate noise exposure appears reversible in C57BL/6J mice.展开更多
K^(+)cycling in the cochlea is critical to maintain hearing.Many sodium-potassium pumps are proved to participate in K^(+)cycling,such as Na/K-ATPase.Theα2-Na/K-ATPase is an important isoform of Na/K-ATPase.The expre...K^(+)cycling in the cochlea is critical to maintain hearing.Many sodium-potassium pumps are proved to participate in K^(+)cycling,such as Na/K-ATPase.Theα2-Na/K-ATPase is an important isoform of Na/K-ATPase.The expression ofα2-Na/K-ATPase in the cochlea is not clear.In this study,we used C57BL/6 mice as a model of presbycusis and implemented immunohistochemistry staining and quantitative real time-PCR,and theα2-Na/K-ATPase expression pattern was confirmed in the inner ear.It was foundα2-Na/K-ATPase was expressed widely in cochlea and its mRNA and protein expression was gradually reduced with aging(4-,14-,26-and 48-weeks old mice).We suspected that,the down-regulation ofα2-Na/K-ATPase expression might be associated with the remodeling of K^(+)cycling,degeneration of morphological structure and decrease of hearing function in aging C57 mice.In conclusion,we speculated that the reduction ofα2-Na/K-ATPase might play an important role in the pathogenesis of age-related hearing loss.展开更多
Four embryonic stem (ES) cell lines, designated CE1, CE2, CE3 and CE4, were isolated from C57BL/6J blastocysts. The ratio of normal diploid composition of these cell lines is above 70%. To examine the differentiation...Four embryonic stem (ES) cell lines, designated CE1, CE2, CE3 and CE4, were isolated from C57BL/6J blastocysts. The ratio of normal diploid composition of these cell lines is above 70%. To examine the differentiation potential of the ES cells, the CE2 cells were injected subcutaneously into syngenic mice, and many kinds of differentiated cells were observed on the sections of the teratoma derived from this ES cell line. On the other hand, to test the chimeric ability of the ES cells, the CE2 cells were microinjected into the blastocysts of ICR mice, and a chimera was obtained among living pups. These results show that CE2 ES cells are pluripotent stem cells, which can differentiate into many kinds of cell types, and can be used as a cell system for further research.展开更多
The purpose of this study was to evaluate the influence of squalene (SQ) on plasma and hepatic lipid levels of obese/diabetic KK-Ay mice and wild-type C57BL/6J mice. SQ supplementation significantly increased the HDL ...The purpose of this study was to evaluate the influence of squalene (SQ) on plasma and hepatic lipid levels of obese/diabetic KK-Ay mice and wild-type C57BL/6J mice. SQ supplementation significantly increased the HDL cholesterol of KK-Ay mice, which was paralleled with no significant difference in the total and non-HDL cholesterol levels. The increase in HDL cholesterol was also found in the plasma of normal C57BL/6J mice, but the difference was not significant. SQ administration significantly increased neutral lipids (NL) in the liver of KK-Ay mice, while no significant difference was observed in the polar lipids and the total cholesterol levels. The increase in NL was primarily due to the increase in TAG. However, the cholesterol level significantly increased due to SQ intake in the liver of C57BL/6J mice, while no significant difference was found in other lipid levels. The present study suggests that SQ may effectively increase HDL cholesterol level, an important anti-atherosclerotic factor, especially in subjects with metabolic disorders.展开更多
Eclipta prostrata has been extensively studied for its promoting effect on human health. Previous study proved that E. prostrata possessed anti-osteoporosis function in SAMP6 mice via gut microbiota (GM). Endophytes a...Eclipta prostrata has been extensively studied for its promoting effect on human health. Previous study proved that E. prostrata possessed anti-osteoporosis function in SAMP6 mice via gut microbiota (GM). Endophytes are widespread in plants, especially in Chinese herbal medicines. However, little is known regarding the endophytes of E. prostrata. In this study, we focus on screening and identifying the endophytes from plant E. prostrata and exploring their roles in modulating GM. According to biochemical, physiological tests and 16S rDNA sequence analysis, ten endophytes were characterized in different locations of plant E. prostrata belonging to Lactococcus, Bacillus, Enterococcus, Exiguobacterium and Pantoea. The antimicrobial activity of endophytes EP01-10 was investigated via the oxford cup method. Furthermore, the acid and bile salt resistant ability of EP01-10 was detected to explore their survival ability in gastrointestinal tract. Results indicated that strains of Lactococcus, Bacillus and Exiguobacterium (EP01, 03 and 05) showed strong antimicrobial activity against Escherichia coli and Staphylococcus aureus and strains of Lactococcus, Bacillus and Enterococcus (EP01, 02, 04, 08 and 10) have the ability to survive in the gastrointestinal tract. 16S rRNA sequencing of GM in C57BL/6J mice was performed for diversity and structure analysis responded to the administration of E. prostrata extract. E. prostrata extract acted on improving the microflora diversity, particularly in increasing the abundance of Lactococcus significantly. Thus, as an endophyte, Lactococcus plays an important role in E. prostrata modulating intestinal tract. Our study suggested that endophytes of Chinese herbal medicines might be a novel target for the treatment of diseases by regulating the GM.展开更多
Dear Editor,As of June,2020,more than ten million cases of COVID-19 have been reported worldwide.The causative pathogen of the disease is a novel coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-...Dear Editor,As of June,2020,more than ten million cases of COVID-19 have been reported worldwide.The causative pathogen of the disease is a novel coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)(World Health Organization,2020).Animal infection models are important to characterize the infection,pathogenesis,and immunology of SARS・CoV・2,as well as for the development of medications and vaccines against COVID-19.Mice are particularly attractive animal models for their identical genetic background,reliable reproducibility,well characterized biology,and the huge availability of research reagents and knockout animals.Models in inbreed mice such as BALB/c and C57BL/6J(C57),which are widely used in research,are highly desired.展开更多
A new method for establishing ES cell lines from 129/ter、C57BL/6J mice was set up which was characterized by the murine embryonic fibroblast cell(MEF) feeder, the medium of rat heart cell-conditioned medium(RH-CM)for...A new method for establishing ES cell lines from 129/ter、C57BL/6J mice was set up which was characterized by the murine embryonic fibroblast cell(MEF) feeder, the medium of rat heart cell-conditioned medium(RH-CM)for ES cells, and the consecutive digestion by the digestion liquid containing 1% serum. Every group of improved experiments was done with a control of routine method. The results showed that, compared with routine method, the improved way increased the ratio of ES cell lines of 129/ter mice from 11.8% to 33.3%, and of C57BL/6J from 3.7% to 13.3%. The difference is distinct. The passage culture of ES cells showed that, compared with medium added LIF, RH-CM not only inhibited the differentiation of murine ES cells, maintained its dipoild karyotype, but also promote its adherence growth. This kind of culture condition not only maintained the ES cells in an undifferentiated state and their normal dipoild karyotype, but also a series of other characteristics of totipotent embryonic stem cells during extended culture period.展开更多
基金supported by grants from the Liaoning Science and Technology Project(No.2011225017,2012225021)the National Basic Research Program of China(973 Program)(2012CB967900,2012CB967901)+2 种基金supported by the grants from the Beijing Natural Science Foundation(5122040)the China Postdoctoral Science Foundation(201003779,20100470103)the National Natural Science Foundation of China(NSFC,31040038)
文摘Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice. Methods Male C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice were randomly sclccted to be studied immediately after exposure （Group P0）, or 1 day （Group P1）, 3 days （Group P3）, 7 day （Group P7） or 14 days （P14） after exposure. Their before exposure condition served as the normal control. All mice were exposed to a broad-band white noise at 100 dB SPL for 2 hours, ABR thresholds were used to estimate hearing status at each time point. Results ABR threshold elevation was seen at every tested frequency at P0 （P〈0.01）. Elevation at high-frequencies （16 kHz and 32 kHz） was greater than at lower frequencies （4 kHz and 8 kHz, P〈0.05）. From P1 to P14, ABR thresholds continuously improved, and there was no significant difference between P14 and before exposure （P〉0.05）. Conclusion There is a frequency specific re- sponse to 100 dB SPL broad-band white noise in C57BL/6J mice, with the high-frequency being more susceptible. Hearing loss induced by moderate noise exposure appears reversible in C57BL/6J mice.
基金National Natural Science Foundation of China(Nos.81771004,81271078,81500791,81500794 and 81300827).
文摘K^(+)cycling in the cochlea is critical to maintain hearing.Many sodium-potassium pumps are proved to participate in K^(+)cycling,such as Na/K-ATPase.Theα2-Na/K-ATPase is an important isoform of Na/K-ATPase.The expression ofα2-Na/K-ATPase in the cochlea is not clear.In this study,we used C57BL/6 mice as a model of presbycusis and implemented immunohistochemistry staining and quantitative real time-PCR,and theα2-Na/K-ATPase expression pattern was confirmed in the inner ear.It was foundα2-Na/K-ATPase was expressed widely in cochlea and its mRNA and protein expression was gradually reduced with aging(4-,14-,26-and 48-weeks old mice).We suspected that,the down-regulation ofα2-Na/K-ATPase expression might be associated with the remodeling of K^(+)cycling,degeneration of morphological structure and decrease of hearing function in aging C57 mice.In conclusion,we speculated that the reduction ofα2-Na/K-ATPase might play an important role in the pathogenesis of age-related hearing loss.
文摘Four embryonic stem (ES) cell lines, designated CE1, CE2, CE3 and CE4, were isolated from C57BL/6J blastocysts. The ratio of normal diploid composition of these cell lines is above 70%. To examine the differentiation potential of the ES cells, the CE2 cells were injected subcutaneously into syngenic mice, and many kinds of differentiated cells were observed on the sections of the teratoma derived from this ES cell line. On the other hand, to test the chimeric ability of the ES cells, the CE2 cells were microinjected into the blastocysts of ICR mice, and a chimera was obtained among living pups. These results show that CE2 ES cells are pluripotent stem cells, which can differentiate into many kinds of cell types, and can be used as a cell system for further research.
文摘The purpose of this study was to evaluate the influence of squalene (SQ) on plasma and hepatic lipid levels of obese/diabetic KK-Ay mice and wild-type C57BL/6J mice. SQ supplementation significantly increased the HDL cholesterol of KK-Ay mice, which was paralleled with no significant difference in the total and non-HDL cholesterol levels. The increase in HDL cholesterol was also found in the plasma of normal C57BL/6J mice, but the difference was not significant. SQ administration significantly increased neutral lipids (NL) in the liver of KK-Ay mice, while no significant difference was observed in the polar lipids and the total cholesterol levels. The increase in NL was primarily due to the increase in TAG. However, the cholesterol level significantly increased due to SQ intake in the liver of C57BL/6J mice, while no significant difference was found in other lipid levels. The present study suggests that SQ may effectively increase HDL cholesterol level, an important anti-atherosclerotic factor, especially in subjects with metabolic disorders.
文摘Eclipta prostrata has been extensively studied for its promoting effect on human health. Previous study proved that E. prostrata possessed anti-osteoporosis function in SAMP6 mice via gut microbiota (GM). Endophytes are widespread in plants, especially in Chinese herbal medicines. However, little is known regarding the endophytes of E. prostrata. In this study, we focus on screening and identifying the endophytes from plant E. prostrata and exploring their roles in modulating GM. According to biochemical, physiological tests and 16S rDNA sequence analysis, ten endophytes were characterized in different locations of plant E. prostrata belonging to Lactococcus, Bacillus, Enterococcus, Exiguobacterium and Pantoea. The antimicrobial activity of endophytes EP01-10 was investigated via the oxford cup method. Furthermore, the acid and bile salt resistant ability of EP01-10 was detected to explore their survival ability in gastrointestinal tract. Results indicated that strains of Lactococcus, Bacillus and Exiguobacterium (EP01, 03 and 05) showed strong antimicrobial activity against Escherichia coli and Staphylococcus aureus and strains of Lactococcus, Bacillus and Enterococcus (EP01, 02, 04, 08 and 10) have the ability to survive in the gastrointestinal tract. 16S rRNA sequencing of GM in C57BL/6J mice was performed for diversity and structure analysis responded to the administration of E. prostrata extract. E. prostrata extract acted on improving the microflora diversity, particularly in increasing the abundance of Lactococcus significantly. Thus, as an endophyte, Lactococcus plays an important role in E. prostrata modulating intestinal tract. Our study suggested that endophytes of Chinese herbal medicines might be a novel target for the treatment of diseases by regulating the GM.
文摘Dear Editor,As of June,2020,more than ten million cases of COVID-19 have been reported worldwide.The causative pathogen of the disease is a novel coronavirus named severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)(World Health Organization,2020).Animal infection models are important to characterize the infection,pathogenesis,and immunology of SARS・CoV・2,as well as for the development of medications and vaccines against COVID-19.Mice are particularly attractive animal models for their identical genetic background,reliable reproducibility,well characterized biology,and the huge availability of research reagents and knockout animals.Models in inbreed mice such as BALB/c and C57BL/6J(C57),which are widely used in research,are highly desired.
文摘A new method for establishing ES cell lines from 129/ter、C57BL/6J mice was set up which was characterized by the murine embryonic fibroblast cell(MEF) feeder, the medium of rat heart cell-conditioned medium(RH-CM)for ES cells, and the consecutive digestion by the digestion liquid containing 1% serum. Every group of improved experiments was done with a control of routine method. The results showed that, compared with routine method, the improved way increased the ratio of ES cell lines of 129/ter mice from 11.8% to 33.3%, and of C57BL/6J from 3.7% to 13.3%. The difference is distinct. The passage culture of ES cells showed that, compared with medium added LIF, RH-CM not only inhibited the differentiation of murine ES cells, maintained its dipoild karyotype, but also promote its adherence growth. This kind of culture condition not only maintained the ES cells in an undifferentiated state and their normal dipoild karyotype, but also a series of other characteristics of totipotent embryonic stem cells during extended culture period.
