• Parasites, Hosts and Diseases
• /
• v.30 no.3
• /
• pp.169-176
• /
• 1992

In order to compare the intraspecific variation in host-parasite relationship of Clonorchis sinensis, six strains of inbred mice, ICR, DDY, GPC, BALB/c, nude and DS, were infected orally with 20 metacercariae of C. sinensis. The biologic incubation period of C. sinensis was the shortest in DDY mice, 21.2 days in average, followed by GPC 21.4, BALB/c and DS 23.2, ICR and nude 23.4 days, respectively. The fertile period of the cuke was also the longest in the DDY strain, 164 days on average, followed by GPC 132, BALB/c 97, nude 37, DS 32 and ICR 28 days. The egg-laying capacity of the cuke in DDY and GPC was relatively high and stable compared with the other four strains of mice. It was found that there are intraspecific variations in biologic incubation period, fertile period, and fecundity of C. sinensis. The DDY mouse is likely to be the most suitable experimental animal among the six strains of the mice tested. Key words: Mouse strain, Clonorchis sinensis, egg-laying capacity.

• Biomolecules & Therapeutics
• /
• v.22 no.5
• /
• pp.453-459
• /
• 2014

Chronic mild stress (CMS) has been reported to induce an anhedonic-like state in mice that resembles some of the symptoms of human depression. In the present study, we used a chronic mild stress animal model of depression and anxiety to examine the responses of two strains of mice that have different behavioral responsiveness. An outbred ICR and an inbred C57BL/6 strain of mice were selected because they are widely used strains in behavioral tests. The results showed that the inbred C57BL/6 and outbred ICR mice were similarly responsive to CMS treatment in sucrose intake test (SIT) and open field test (OFT). However, the two strains showed quite different responses in forced swimming test (FST) and novelty-suppressed feeding (NSF) test after 3 weeks of CMS treatment. Only C57BL/6 mice displayed the depression- and anxiety-like behavioral effects in response to CMS treatment in FST and NSF test. Our results suggest that there are differences in responsiveness to CMS according to the different types of strain of mice and behavioral tests. Therefore, these results provide useful information for the selection of appropriate behavioral methods to test depression- and anxiety-like behaviors using CMS in ICR and C57BL/6 mice.

• Korean Journal of Animal Reproduction
• /
• v.10 no.1
• /
• pp.27-35
• /
• 1986

As a preliminary experiment to establish the process on the sexing of mouse embryos by chromosomal analysis, present studies were carried out with inbred (ICR, C57BL) and F1 hybrid [(ICR${\times}$C57BL) = F1 ${\times}$ ICR] mice to investigate the blastomere numbers and mitotic indices (M.I.) to the developmental stage of embryos recovered, the optimum periods of anti-mitotic agent administration, the successful rates of sexing and sex-ratio. The results obtained were summarized as follows: 1. The blastomere numbers (mean${\pm}$S.E.) of the morula and blastocyst were 18${\pm}$0.4 and 54${\pm}$0.7, respectively. 2. Whereas the M.I. of F1 hybrid (16${\pm}$0.2%) was higher than that fo inbred ICR (15${\pm}$0.1%) and C57BL (12${\pm}$0.6%) in the different strains, the morula (7${\pm}$0.6%) was higher than that of blastocyst (6${\pm}$0.4%) in the case of embryo stages. 3. Following to anti-mitotic agents treated, the M.I. of embryos cultured with Colcemid (17${\pm}$1.1%) was superior to that fo embryos cultured with Velban (12${\pm}$0.9%) and the Colcemid injection (7${\pm}$0.4%). 4. The successful rate of sexing in the blastocyst (38.7%; 124/320) was superior to the morula (35.9%; 52/145), and the F1 hybrid (48.1%) was higher than that of inbred ICR (42.4%) and C57 BL (28.2%). 5. In the successful rate of sexing to the methods of administration, the embryos cultured with Colcemid (46.0%) was superior to that of embryos cultured with Velban (39.0%) and the Colcemid injection (38.8%). 6. Of 98 embryos sexed after culture with Colcemid, 89(90.8%) were observed between 2 and 4 hrs. In the case of Velban treatment, 83.1% (74/89) was observed between 2$\frac{1}{2}$ and 4$\frac{1}{2}$ hrs. 7. Out of 761 prepared embryos it was possible to sex 311; 157 were male and 154 were female, i.e.a sex-ratio of 50% a, pp.oximately.

• Journal of Animal Reproduction and Biotechnology
• /
• v.35 no.1
• /
• pp.86-93
• /
• 2020

The establishment of porcine embryonic stem cells (ESCs) from porcine somatic cell nuclear transfer (SCNT) blastocysts is influenced by in vitro culture day of porcine reconstructed embryo and feeder cell type. Therefore, the objective of the present study was to determine the optimal in vitro culture period for reconstructed porcine SCNT embryos and mouse embryonic fibroblast (MEF) feeder cell type for enhancing colony formation efficiency from the inner cell mass (ICM) of porcine SCNT blastocysts and their outgrowth. As the results, porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days showed significantly increased efficiency in the formation of colonies, compared to those for 7 days. Moreover, MEF feeder cells derived from outbred ICR mice showed numerically the highest efficiency of colony formation in blastocysts produced through in vitro culture of porcine SCNT embryos for 8 days and porcine ESCs with typical ESC morphology were maintained more successfully over Passage 2 on outbred ICR mice-derived MEF feeder cells than on MEF feeder cells derived from inbred C57BL/6 and hybrid B6CBAF1 mice. Overall, the harmonization of porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days and MEF feeder cells derived from outbred ICR mice will greatly contribute to the successful establishment of ESCs derived from porcine SCNT blastocysts.

• Development and Reproduction
• /
• v.13 no.4
• /
• pp.305-312
• /
• 2009

Multipotent spermatogonial stem cells (mSSCs), derived from uni-potent SSC, are a type of reprogrammed cells with similar characteristics to embryonic stem cells (ESCs). The aim of this study was to evaluate the potential for transgenesis of mSSC derived from outbred mice and the production of transgenic animal by the mSSC-insertion into embryo. mSSCs, established from outbred mice (ICR strain) in the previous study, were maintained and then transfected with a lenti-viral vector expressing green fluorescent protein (GFP), CS-CDF-CG-PRE. Embryonic stem cells (ESCs) were derived from inbred transgenic mice (C57BL/6-Tg (CAG-EGFP)) and were used as an experimental control. Transfected mSSCs were well proliferated in vitro and maintained their characteristics and normal karyotype. Ten to twelve mSSCs and ESCs were collected and inserted into perivitelline space of 8-cell mouse embryos, and then transferred them into uteri of poster mothers after an additional 2-days of culture. Percentage of mSSC-derived offsprings was 4.8% (47/980) and which was lower than those (11.7% (67/572)) of ESC-derived ones (P<0.05). However, even though different genetic background of mSSC and ESC origin, the production efficiency of coat-colored chimeric offspring in mSSC group was not different when compared it with ESC (6.4% (3/47) vs. 7.5% (5/67)). From these results, we confirmed that mSSC derived from outbred mice has a pluripotency and a potential to produce chimeric embryos or mice when reaggregatation with mSSC is performed.

• Korean Journal of Animal Reproduction
• /
• v.12 no.1
• /
• pp.31-36
• /
• 1988

There studies were conducted using inbred ICR mice to examine the sex of preimplantation mouse embryo. The morphological normality of mice embryos treated with the culture medium containing rat H-Y antiserum(10%, v/v) plus complement(20%,v/v) was observed and also the sexing of embryos was investigated by chromosomal analysis. The results obtained were summarized as follows: 1. The viability of preimplantation mouse embryos, which were incubated in vitro with different media condition, was scored 68.9-85.5% in control group. However, 151 embryos normally developed up to blastocyst and 160 embryos were retarded growth or destroyed out of total 311 embryos treated in the medium containing H-Y antiserum(10%, v/v) plus complement(20%,v/v). 2. H-Y antiserum was prepared from inb red rats (Wistar and Donryu strain) with different immunization times (4, 5 and 6th) to examine the specific titer of embryos by the number of immunization. Precentage of normally developed embryos incubated either in the medium containing the antiserum of Wistar plus complement or Donryu plus complement was revealed 50.9, 47.4 and 50.0% (4, 5 and 6th immunization and 47.8, 41.2 and 48.7%, respectively. 3. Twenty two females and five males were identified out of fourty-eight normally developed embryos incubated in the medium containing H-Y antiserum plus complement by chromosomal analysis.

• The Journal of the Korean Society for Microbiology
• /
• v.20 no.1
• /
• pp.115-125
• /
• 1985

Hemorrhagic fever with renal syndrome (HFRS) is a debilitating disease of humans caused by Hantaan virus (HV), the prototype member of a newly proposed genus of Bunyaviridae. Studies of HV pathogenesis have been limited by the absence of a well defined model for a virus-induced disease state. In an attempt to devise a model for HV pathogenesis in laboratory rodents, newborn outbred suckling ICR mice were shown to be uniformly susceptible to lethal infection with non- mouse adapted HV by intracerebral (IC), intraperitoneal (IP), intramuscular (IM), and subcutaneous (SC) inoculation routes. Clinical coures, mean time to death, and fatal outcome were age-dependent. With an inoculum of 10 $LD_{50}$, mortality was 100% in mice infected within 72h of birth, but declined to 50% by 7 days. By 2-2.5 weeks, animals developed complete resistance to clinical disease. Virus was consistently detected in serum by day 6 post-infection in IC- and IP- inoculated animals, and reached peak levels of $10^5\;PFU/ml$ by day 8 Mice infected IM and SC showed delays in onset of viremia, but achieved similar titers. Immunofluorescent antibody appeared by 17-18 days, and neutralizing antibody by 15 days, in all experimental groups. Two of 8 inbred mouse strains were identified as resistant to clinical disease : SJL/J and A/J. Manipulation of this model will allow investigation of natural rodent pathogenesis with HV, as well as offer insight into disease mechanisms and therapy of HFRS.

• Korean Journal of Animal Reproduction
• /
• v.11 no.3
• /
• pp.218-222
• /
• 1987

This study was conducted using inbred ICR mice to investigate the sex-ratio of preimplantation mouse embryos. For the investigation of sex-ratio of mouse embryos, the karyotype of embryos collected at 70-72, 74-76, 78-80 and 82-84 hr after HCG injection was analyzed by chromosomal analysis. Eight-cell embryos were cultrued up to blastocyst stage, then divided them into three groups(fast-, intermediate- and slow-) according to the blastocoel formation. The sex-ratio was also investigated by chromosomal analysis. 1. The highest apperance of eight-cell and morula was observed at the embryos collected respectively at 66-68 hr(84.6%) and 82-84 hr(79.3%) compared to any other group. 2. The successful rate of embryos sexing at 4-, 8-cell and morula stage were 23.1% (3/13), 42.1%(138/328) and 32.6%(47/141), respectively. The respective sex ratios (female vs male) of 4-, 8-cell and morula were 66.7:33.3, 49.3:50.7 and 39.5:60.5. 3. Of the 476 eight-cell embryos cultured in vitro, 427(89.7%) embryos were developed to the blastocysts and the number of fast-, intermediate- and show-developing embryos were 139, 144 and 144, respectively. 4. Female to male ratios fo fast-, intermediate- and slow-developing group were 23.0:77.0, 55.2:44.8 and 73.8:26.2, respectively. Significantly higher (P<0.05) number of female (48/65;73.8%) was observed in the group of slow-developing embryo than that out of total number of embryos(82/188;43.6%).

• Korean Journal of Animal Reproduction
• /
• v.8 no.1
• /
• pp.29-35
• /
• 1984

These experiments were carried out to obtain basic information necessary for in vitro culture of aggregated mouse embryos. Inbred ICR mice were used to obtain embryos. The zona pellucida was removed by placing the embryos in Whittingham's medium containing 0.5% protease for about 5-10minutes at 37$^{\circ}C$. Total 263 pairs of 2-, 4- and 8-cell zona free mouse embryos were subjected to aggregation by physical pressure and cultured in Whittingham's medium under the gas phase of 5% CO2 in air at 37$^{\circ}C$ for 24 to 60 hours. The results obtained in these experiments were summarized as follows: 1. Time needed for fusion of 2-, 4- and 8-cell embryos were 0-3, 0-3 and 0-3 hours, respectively and average time needed for in vitro development of 2-, 4- and 8-cell embryos after aggregation to morula and blastocyst were 42, 30 and 13.5 hours, and 51, 39 and 27 hours, respectively. 2. Of total 263 pairs of naked embryos, 227 were firmly aggregated together and the rats of aggregation in 2-, 4- and 8-cell embryos were 71.8, 88.3 and 97.0%, respectively. 3. The rates of aggregated pairs which obtained from 2-, 4- and 8-cell embryos developed to morula were 96.7, 95.6 and 96.9%, respectively, and embryos developed to blastocysts were 88.5, 89.7 and 90.8%, respectively. 4. Conspicuous differences in size of volume and inner cell masses between single and double blastocysts were observed. Although a single blastocolic cavity was formed in most double blastocysts, several formed two distinct cavities from the very beginning.

• Clinical and Experimental Reproductive Medicine
• /
• v.38 no.1
• /
• pp.24-30
• /
• 2011

Objective: The objectives of this study were to analyze efficacy of immature and mature mouse oocytes after vitrification and warming by applying various combinations of cryoprotectants (CPAs) and/or super-rapid cooling using slush nitrogen ($SN_2$). Methods: Four-week old ICR female mice were superovulated for GV- and MII-stage oocytes. Experimental groups were divided into two groups. Ethylene glycol (EG) only group: pre-equilibrated with 1.5 M EG for 2.5 minutes and then equilibrated with 5.5 M EG and 1.0 M sucrose for 20 seconds. EG+dimethylsulfoxide (DMSO) group: pre-equilibrated with 1.3 M EG+1.1 M DMSO for 2.5 minutes and equilibrated with 2.7 M EG+2.1 M DMSO+0.5 M sucrose for 20 seconds. The oocytes were loaded onto grids and plunged into $SN_2$or liquid nitrogen ($LN_2$). Stored oocytes were warmed by a five-step method, and then their survival, maturation, cleavage, and developmental rates were observed. Results: The EG only and EG+DMSO groups showed no significant difference in survival of immature oocytes vitrified after warming. However, maturation and cleavage rates after conventional insemination were greater in the EG only group than in the EG+DMSO group. In mature oocytes, survival, cleavage, and blastocyst formation rates after warming showed no significant difference when EG only or EG+DMSO was applied. Furthermore, cleavage and blastocyst formation rates of MII oocytes vitrified using $SN_2$ were increased in both the EG only and EG+DMSO groups. Conclusion: A combination of CPAs in oocyte cryopreservation could be formulated according to the oocyte stage. In addition, $SN_2$ may improve the efficiency of vitrification by reducing cryoinjury.