Metastatic human hepatocellular carcinoma models in nude mice and cell line with metastatic potential

Metastatic human HCC model is needed for the studies on mechanism and intervention of metastatic recurrence. By using orthotopic implantation of histologically intact tissues of 30 surgical specimens, a patient-like metastatic model of human HCC in nude mice (LCI-D20) and a low metastatic model of human HCC in nude mice (LCI-D35) have been established. All mice with transplanted LCI-D20 tumors exhibited extremely high metastatic ability including spontaneous metastasis to liver, lungs, lymph nodes and peritoneal seeding. Remarkable difference was also found in expression of some of the invasiveness related genes and growth factors between the LCI-D20 and LCI-D35 tumors. PAI-1 increased gradually following tumor progression in LCI-D20 model, and correlated with tumor size and AFP level. Phasic expression of tissue intercellular adhesion molecule-1 in this model was also observed. Using corneal micropocket model, it was demonstrated that the vascular response induced by LCI-D20 tumor was stronger than that induced by LCI-D35 tumor. Similar report on metastatic human HCC model in nude mice and human HCC cell line with metastatic potential was rarely found in the literature. This LCI-D20 model has been widely used for the studies on intervention of metastasis, including anti-angiogenesis,antisense approach, metalloproteinase inhibitor, differentiation inducer, etc. It is concluded that the establishment of metastatic human HCC model in nude mice and human HCC cell line with metastatic potential will provide important models for the in vitro and in vitro study of HCC invasiveness, angiogenesis as well as intervention of HCC recurrence.

How can we establish animal models of HIV-associated lymphoma?

Human immunodeficiency virus(HIV)infection is strongly associated with a height-ened incidence of lymphomas.To mirror the natural course of human HIV infection,animal models have been developed.These models serve as valuable tools to inves-tigate disease pathobiology,assess antiretroviral and immunomodulatory drugs,ex-plore viral reservoirs,and develop eradication strategies.However,there are currently no validated in vivo models of HIV-associated lymphoma(HAL),hampering progress in this crucial domain,and scant attention has been given to developing animal models dedicated to studying HAL,despite their pivotal role in advancing knowledge.This re-view provides a comprehensive overview of the existing animal models of HAL,which may enhance our understanding of the underlying pathogenesis and approaches for malignancies linked to HIV infection.

Type Ⅰ interferon receptor knockout mice as models for infection of highly pathogenic viruses with outbreak potential

Due to their inability to generate a complete immune response, mice knockout for type I interferon （IFN） receptors （Ifnar-/-） are more susceptible to viral infections, and are thus commonly used for pathogenesis studies. This mouse model has been used to study many diseases caused by highly pathogenic viruses from many families, including the Flaviviridae, Filoviridae, Arenaviridae, Bunyaviridae, Henipaviridae, and Togaviridae. In this review, we summarize the findings from these animal studies, and discuss the pros and cons of using this model versus other known methods for studying pathogenesis in animals.

Research progress on depression models of different strains of rats and mice

The incidence of depression is increasing day by day,and its pathogenesis is characterized by complexity and high recurrence rate.In addition,the pathogenesis has not been elucidated.There are significant differences in the reference indicators between rat and mouse models of different strains.As the experimental modeling of depression is easily affected by gender and modelling methods,it is necessary to standardize the selection of rat and mouse strains for experimental research.Although the widely used rat and mouse models of depression can meet the research on most depression diseases,with the in-depth study of component targets of traditional Chinese medicine(TCM)and the development of diagnosis and treatment of TCM dialectics,the improvement and maturity of the depression animal model that is in line with TCM syndrome classification will have more research values for the basic research of depression in Chinese medicine.Therefore,we summarize and analyze the characteristics of different strains of rats and mice based on contemporary literature in this review,in order to provide a more powerful theoretical basis for the basic research of syndromes on TCM treatment of depression.

Establishment of a mdr1 Multidrug Resistant Model of Orthotopic Transplantation of Liver Carcinoma on Nude Mice

To develop a new method of inducing mdrl multidrug resistance by establishinga nude mice model of orthotopic transplantation of liver carcinoma by sporadic abdominalchemotherapy at intervals. Methods: Hepatocellular carcinoma HepG2 cell was cultured and injectedsubcutaneously to form the tumor-supplying mice. The tumor bits from the tumor-supplying mice wereimplanted under the envelope of the mice liver and induced by abdominal chemotherapy withPharmorubicin. Physical examination, ultrasonography, spiral CT and operative inspection were usedto examine tumor progression. RT-PCR and immunohistochemistry were adopted to detect the expressionof mdr1-mRNA and its encoded protein P-gp protein (P-gp). Results: There was no operative dead, therate of implanting tumor successfully was 88% (22/25), the rate of implanting secondly successfullywas 100% (3/3), and the rate of inducing successfully was 80% (16/20). The expression of mdrl-mRNAand the P-gp in the inducing group was 23 folds and 13 folds in the control group respectively.Conclusion: We have established an in vivo model of mdr using nude mice transplanted with orthotopicliver neoplasm coupled to chemotherapy.

Targeting Effect Study of ￣(3) H-Mitoxantrone Nanosphereson Hepatocellular Carcinoma(HCC) Model in Nude Mice

The distribution of ￣(3)H-mitoxantrone polybutyl cyanoacrylate nanospheres(￣(3)H-DHAQ-PBCA-NS)in the viscera,muscle and tumors of human hepatocellular carcinoma (HCC)model in nude mice was studied with liquid scintillation counting techniique. The results showed that the ￣(3)H-DHAQ-PBCA-NS had remarkable liver targeting effect. The content of ￣(3)H-DHAQ-PBCA-NSin liver and heterotopic liver tumor was found to be 71.31±10. 49% of total amount of drug in animal body. It was also found that the content of ￣(3)H-DHAQ-PBCA-NS in liver was higher than that in liver tissue, and the content of ￣(3)H-DHAQ-PBCA-NS in annpit tumor was higher than that in armpit muscle tissue,but had no significant difference;It provides an ideal preparation for the DHAQ admini-stration.

Kidney disease models:tools to identify mechanisms and potential therapeutic targets

Acute kidney injury （AKI） and chronic kidney disease （CKD） are worldwide public health problems affecting millions of people and have rapidly increased in prevalence in recent years. Due to the multiple causes of renal failure, many animal models have been developed to advance our understanding of human nephropathy. Among these experimental models, rodents have been extensively used to enable mechanistic understanding of kidney disease induction and progression, as well as to identify potential targets for therapy. In this review, we discuss AKI models induced by surgical operation and drugs or toxins, as well as a variety of CKD models （mainly genetically modified mouse models）. Results from recent and ongoing clinical trials and conceptual advances derived from animal models are also explored.

Anti-tumor activities and apoptosis-regulated mechanisms of bufalin on the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice

AIM: To investigate anti-tumor activities and apoptosis-regulated mechanisms of bufalin in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice.METHODS: BEL-7402 cells of human hepatocellular carcinoma were inoculated to form subcutaneous tumors, and were implanted into the liver to establish orthotopic transplantation tumor models of human hepatocellular carcinoma in nude mice. Seventy-five animals were randomized divided into five groups (n = 15). Bufalin was injected intraperitoneally into three groups at doses of 1.5 mg/kg (BF1), 1 mg/kg (BF2) and 0.5 mg/kg (BF3) for d 15-24, respectively. The NS group was injected an equal volume of saline as above and adriamycin was injected intraperitoneally into the ADM group at a dose of 8.0 mg/kg for d 15. Ten mice in each group were killed at d 25 and the survival time in each group was calculated. We also observed the morphologic alterations in the myocardium, brain, liver, kidney and tumor tissues by pathology and electron microscopy, measured the apoptotic rate by TUNEL staining method, and detected the expression of apoptosis-regulated genes bcl-2 and bax by immunohistochemical staining and RT-PCR in tumor tissues. RESULTS: The tumor volumes in each group of bufalin were reduced significantly (35.21 ± 12.51 vs 170.39 ± 25.29; 49.83 ± 11.46 vs 170.39 ± 25.29; 83.99 ± 24.63 vs 170.39 ± 25.29, P < 0.01, respectively), and the survival times were prolonged in group BF1-2 (31.8 ± 4.2 vs 23.4 ± 2.1 and 29.4 ± 3.4 vs 23.4 ± 2.1, P < 0.05, respectively), and necrosis was mainly in severe or moderate degree in group BF1-2. No morphologicalchanges were detected in the myocardium, brain, liver and kidney tissues. Apoptotic characteristics could be seen in group BF1-2. The positive rates of bcl-2 and bax protein expression of each group by immunohistochemical staining were 10.0%, 10.0%, 20.0%, 10.0% and 20.0%; 90.0%, 80.0%, 80.0%, 40.0% and 30.0%, respectively. Loss of expression of bcl-2 mRNA in each group was to be found and the density of bax mRNA was increased progressively with increase of dose of bufalin by RT-PCR. CONCLUSION: Bufalin has significant anti-tumor activities in the orthotopic transplantation tumor model of human hepatocellular carcinoma in nude mice with no marked toxicity and was able to induce apoptosis of transplanted tumor cells. This apoptosis may be mediated mainly via up-regulating the expression of apoptosis-regulated gene bax, which may be involved in its anti-tumor mechanism of bufalin.

Knockout mouse models of insulin signaling: Relevance past and future

Insulin resistance is a hallmark of type 2 diabetes. In an effort to understand and treat this condition, re searchers have used genetic manipulation of mice to uncover insulin signaling pathways and determine the effects of their perturbation. After decades of research much has been learned, but the pathophysiology o insulin resistance in human diabetes remains contro versial, and treating insulin resistance remains a chal lenge. This review will discuss limitations of mouse models lacking select insulin signaling molecule genes In the most influential mouse models, glucose metabo lism differs from that of humans at the cellular, organ and whole-organism levels, and these differences limi the relevance and benefit of the mouse models both in terms of mechanistic investigations and therapeutic development. These differences are due partly to im mutable differences in mouse and human biology, and partly to the failure of genetic modifications to produce an accurate model of human diabetes. Several fac tors often limit the mechanistic insights gained from experimental mice to the particular species and strain including: developmental effects, unexpected meta bolic adjustments, genetic background effects, and technical issues. We conclude that the limitations and weaknesses of genetically modified mouse models of insulin resistance underscore the need for redirection of research efforts toward methods that are more directly relevant to human physiology.

OB glue paste technique for establishing nude mouse human gastric cancer orthotopic transplantation models

AIM： To establish nude mouse human gastric cancer orthotopic transplantation models using OB glue paste technique. METHODS： Using OB glue paste technique, orthtopic transplantation models were established by implanting SGC-7901 and NKN-45 human gastric cancer cell strains into the gastric wall of nude mice. Biological features, growth of the implanted tumors, the success rate of transplantation and the rate of auto-metastasis of the two models were observed. RESULTS： The success rates of orthotopic transplanration of the two models were 94.20% and 96%. The rates of hepatic metastasis, pulmonary metastasis, peritoneal metastasis, lymphocytic metastasis and splenic metastasis were 42.13% and 94.20%, 48.43% and 57.97%, 30.83% and 36.96%, 67.30% and 84.06%, and 59.75% and 10.53%, respectively. The occurrence of ascites was 47.80% and 36.96%. CONCLUSION： OB glue paste technique is easy to follow. The biological behaviors of the nude mouse human gastric cancer orthotopic transplantation models established with this technique are similar to the natural processes of growth and metastasis of human gastric cancer, and, therefore, can be used as an ideal model for experimental research of proliferative metastasis of tumors.

Mouse models in liver cancer research:A review of current literature

Primary liver cancer remains one of the most lethal malignancies worldwide. Due to differences in prevalence of etiological factors the incidence of primary liver can-cer varies among the world, with a peak in East-Asia. As this disease is still lethal in most of the cases, research has to be done to improve our understanding of the disease, offering insights for possible treatment options. For this purpose, animal models are widely used, especially mouse models. In this review, we describe the different types of mouse models used in liver cancer research, with emphasis on genetically engineered mice used in this field. We focus on hepatocellular carcinoma (HCC), as this is by far the most common type of primary liver cancer, accounting for 70%-85% of cases.

Can outbred mice be used as a mouse model of mild cognitive impairment?

Deficits in spatial learning and memory are some of the earliest symptoms in mild cognitive impairment （MCI）. However, there are few valid MCI animal models available to evaluate putative therapeutic strategies. The aim of this study was to obtain a natural animal model of MCI. Outbred Kunming （aged 5 and 12.5 months） and ICR （7 and 12 months） mice were utilized in the present study. Morris water maze and radial six-arm water maze （RAWM） were simultaneously used to evaluate impaired spatial learning and memory in middle-aged mice （approximately 12 months of age）. Compared with younger mice in the respective groups, the middle-aged mice suffered visible impairment of spatial memory in the Morris water maze and RAWM, and mild spatial learning deficiency occurred in the RAWM study alone. Thus outbred Kunming and ICR mice could be utilized as a natural animal model for MCI, in particular for memory impairment studies.

Translational pancreatic cancer research:a comparative study on patient-derived xenograft models

AIM To assess the viability of orthotopic and heterotopic patient-derived pancreatic cancer xenografts implanted into nude mice.METHODS This study presents a prospective experimental analytical follow-up of the development of tumours in mice upon implantation of human pancreatic adenocarcinoma samples. Specimens were obtained surgically from patients with a pathological diagnosis of pancreatic adenocarcinoma. Tumour samples from pancreatic cancer patients were transplanted into nude mice in three different locations(intraperitoneal, subcutaneous and pancreatic). Histological analysis(haematoxylin-eosin and Masson's trichrome staining) and immunohistochemical assessment of apoptosis(TUNEL), proliferation(Ki-67), angiogenesis(CD31) and fibrogenesis(α-SMA) were performed. When a tumour xenograft reached the target size, it was reimplanted in a new nude mouse. Three sequential tumour xenograft generations were generated(F1, F2 and F3).RESULTS The overall tumour engraftment rate was 61.1%. The subcutaneous model was most effective in terms of tissue growth(69.9%), followed by intraperitoneal(57.6%) and pancreatic(55%) models. Tumour development was faster in the subcutaneous model(17.7 ± 2.6 wk) compared with the pancreatic(23.1 ± 2.3 wk) and intraperitoneal(25.0 ± 2.7 wk) models(P = 0.064). There was a progressive increase in the tumour engraftment rate over successive generations for all three models(F1 28.1% vs F2 71.4% vs F3 80.9%, P < 0.001). There were no significant differences in tumour xenograft differentiation and cell proliferation between human samples and the three experimental models among the sequential generations of tumour xenografts. However, a progressive decrease in fibrosis, fibrogenesis, tumour vascularisation and apoptosis was observed in the three experimental models compared with the human samples. All three pancreatic patient-derived xenograft models presented similar histological and immunohistochemical characteristics.CONCLUSION In our experience, the faster development andgreatest number of viable xenografts could make the subcutaneous model the best option for experimentation in pancreatic cancer.

Effects of strain, body mass, and thread tip preparation on the establishment of focal cerebral ischemia mouse models

BACKGROUND： What are the successful factors of the establishment of the thread-blocking method for focal cerebral ischemia/reperfusion mouse models？ OBJECTIVE： To study the effects of strain, body mass, and thread tip preparation for the establishment of focal cerebral ischemia mouse models by using middle cerebral artery occlusion （MCAO）. DESIGN： Observational contrast animal study. SETTING： Gulou Hospital, Medical College of Nanjing University. MATERIALS： （1） The following experiment was performed at the Animal Experimental Center, Gulou Hospital Affiliated to Medical College of Nanjing University from December 2006 to April 2007. Sixty male white Kunming mice, whose body masses were 18-22 g （n =40）, 25-29 g （n =10） and 30-33 g （n =10）, as well as 10 male C57BL/6J mice, whose body mass was 18-22 g, were provided by the Animal Experimental Center, Gulou Hospital Affiliated to Medical College of Nanjing University. All mice were 10-12 weeks old. The project received confirmed consent from the local ethics committee. （2）Experimental materials： tripheryltetrazolium hydrochloride （TTC） and 0.1% poly-L-lysine were provided by Sigma Company, USA; citromint was provided by Shanghai Lingfeng Chemical Company Limited. METHODS： （1） Strain comparison： Ten white Kunming mice （weighing 18-22 g） and ten C57BL/6J mice （weighing 18 - 22 g） were selected. （2） Comparison of body mass： Thirty white Kunming mice, whose body masses were 18-22 g （n =10）, 25-30 g （n =10）, and 30-35 g （n =10）, were divided into groups. （3） Comparison of thread tip preparation： White Kunming mice weighing 18-22 g were divided into a poly-L-lysine line group and general line group, with 10 mice in each group. Mice in these two groups, which were respectively treated with poly-L-lysine or nothing, underwent MCAO. （4） All experimental mice received MCAO. Three hours after ischemia, and 24 hours after reperfusion, neurological deficit scores were measured and a success rate of model establishment was calculated. In addition, after sacrifice, sample tissues were cut into coronal sections to calculate the cerebral infarction area. MAIN OUTCOME MEASURES： （1） Success rate of model establishment and cerebral infarction area. （2） Neurological deficit scores. RESULTS： Sixty white Kunming mice and 10 C57BL/6J mice were included in the final analysis. （1） Strain comparison： The cerebral infarction area of white Kunming mice was larger than the C57BL/6J mice, and the neurological deficit scores of white Kunming mice were greater than those of the C57BL/6J mice （P 〈 0.05）. （2） Comparison of body mass： A success rate of model establishment in white Kunming mice weighing 18-22 g was higher than in white Kunming mice weighing 25-30 g or 30-35 g （P 〈 0.05）. （3） Comparison of thread tip preparation： The cerebral infarction area of mice in the poly-L-lysine line group was larger than in mice in the general line group. The neurological deficit scores of mice in the poly-L-lysine line group were greater than in mice in the general line group （P 〈 0.05）. CONCLUSION： Strain, body mass, and thread tip preparation can affect the establishment success rate of a focal cerebral ischemia mouse model using MCAO.

Establishment of an orthotopic transplantation tumor model of hepatocellular carcinoma in mice

AIM:To improve the outcome of orthotopic transplantation in a mouse model,we used an absorbable gelatin sponge(AGS) in nude mice to establish an orthotopic implantation tumor model.METHODS:MHCC-97L hepatocellular carcinoma(HCC)cells stably expressing the luciferase gene were injected into the subcutaneous region of nude mice.One week later,the ectopic tumors were harvested and transplanted into the left liver lobe of nude mice.The AGS was used to establish the nude mouse orthotopic implantation tumor model.The tumor suppressor gene,paired box gene 5(PAX5),which is a tumor suppressor in HCC,was transfected into HCC cells to validate the model.Tumor growth was measured by bioluminescence imaging technology.Semi-quantitative reverse transcription polymerase chain reaction(RT-PCR) and histopathology were used to confirm the tumorigenicity of the implanted tumor from the MHCC-97L cell line.RESULTS:We successfully developed an orthotopic transplantation tumor model in nude mice with the use of an AGS.The success rate of tumor transplantation was improved from 60% in the control group to 100% in the experimental group using AGS.The detection of fluorescent signals showed that tumors grew in all live nude mice.The mice were divided into 3 groups:AGS-,AGS+/PAX5-and AGS+/PAX5 +.Tumor size was significantly smaller in PAX5 transfected nude mice compared to control mice(P < 0.0001).These fluorescent signal results were consistent with observations made during surgery.Pathologic examination further confirmed that the tissues from the ectopic tumor were HCC.Results from RT-PCR proved that the HCC originated from MHCC-97L cells.CONCLUSION:Using an AGS is a convenient and efficient way of establishing an indirect orthotopic liver transplantation tumor model with a high success rate.

Lipopolysaccharide mouse models for Parkinson's disease research:a critical appraisal

Parkinson's disease,the most common movement disorder,has a strong neuroinflammatory aspect.This is evident by increased pro-inflammatory cytokines in the serum,and the presence of activated microglial cells,and inflammatory cytokines in the substantia nigra of post-mortem brains as well as cerebrospinal fluid of Parkinson's disease patients.The central and peripheral neuroinflammatory aspects of Parkinson's disease can be investigated in vivo via administration of the inflammagen lipopolysaccharide,a component of the cell wall of gram-negative bacteria.In this mini-review,we will critically evaluate different routes of lipopolysaccharide administration(including intranasal systemic and ste reotasic),their relevance to clinical Parkinson's disease as well as the recent findings in lipopolysaccharide mouse models.We will also share our own expe riences with systemic and intrastriatal lipopolysaccharide models in C57BL/6 mice and will discuss the usefulness of lipopolysaccharide mouse models for future research in the field.

Establishment of Xenotransplantation Model of Human CN-AML with FLT3-ITD^(mut)/NPM1 in NOD/SCID Mice

Summary： Patients with FLT3-ITD^mmutt/NPM1- cytogenetically normal acute myeloid leukemia （CN-AML）, as high-risk molecular group in CN-AML, are associated with a worse prognosis than other CN-AML patients. It is beneficial to generate xenotransplantation model of FLT3-ITD^mut/NPM1- CN-AML to better understand the pathogenesis and therapeutic strategies of such AML subtype. The purpose of present study was to establish the xenotransplantation model in NOD/SCID mice with FLT3-ITD^mut/NPM1- CN-AML primary cells. The FLT3-ITD^mut/NPM1- CN-AML primary cells from 3 of 7 cases were successfully transplanted into NOD/SCID mice, and human CD45 positive cells were detected in the peripheral blood, spleen and bone marrow of mice by using flow cytometry. Infiltration of human leukemia cells in various organs of mice was observed by using immunohistochemistry. Gene analysis confirmed sustained FLT3/ITD mutation without NPM1 mutation in mice. By performing serial transplantation, it was found that characteristics of the leukemia cells in secondary and tertiary genera- tion models remained unchanged. Moreover, in vivo cytarabine administration could extend survival of NOD/SCID mice, which was consistent with clinical observation. In conclusion, we successfully estab- lished xenotransplantation model of human FLT3-ITD^mut/NPM1- CN-AML in NOD/SCID mice. The model was able to present primary disease and suitable to evaluate the curative effects of new drugs or therapy strategies.

Animal models for studying hepatitis C and alcohol effects on liver

Chronic consumption of ethanol has a dramatic effect on the clinical outcome of patients with hepatitis C virus (HCV) infection, but the mechanism linking these two pathologies is unknown. Presently, in vitro systems are limited in their ability to study the interaction between a productive wild-type HCV infection and chronic ethanol exposure. Mouse models are potentially very useful in dissecting elements of the HCV-ethanol relationship. Experiments in mice that transgenically express HCV proteins are outlined, as are experiments for the generation of mice with chimeric human livers. The latter models appear to have the most promise for accurately modeling the effects of chronic ethanol intake in HCV-infected human livers.

Study of Candida Albicans Vaginitis Model in Kunming Mice

The model of vaginal candidiasis in Kunming mice was constructed in order to search for the optima construction conditions and provide an economic animal model of Candida albicans (C. albicans) vaginitis. Estrogen benzoate (E2) was given to mice at different concentrations ranging from 0.0 to 0.05 mg/mouse (4 levels) beginning 72 h prior to vaginal inoculation, then mice were in- oculated intravaginally with various concentrations of stationary-phase C. albicans blastoconidia (ATCC90028) (5 levels) in 20 μL of phosphate-buffered saline (PBS) in each E2 level. General state, scores of genital pathology, the hyphae and vaginal fungal burden (CFU) in vaginal lavage fluid, the hydrops rate of uterus and vaginal tissues for pathological section in mice were observed and ob- tained at day 2, 4, 7, 14 and 21 after inoculation. The results showed the infection rate in mice was related to the dosage of E2 and concentration of C. albicans blastoconidia. Additionally there was better cross-effect between the two treated factors. The infection rate was about 80% on the day 4, and could reach 100% on the day 7 until the end of experiment after inoculated intravaginally in groups of E2I3, E2 0.025 mg/mouse injected hypodermically and inoculated intravaginally with 5×104 C. albicans blastoconidia, and large amount of hyphae and blastoconidia could be observe in superfi- cial layer tissue and canal of vaginal by PAS. From the results in our experiment it was concluded that E2I3 was the optima construction condition in kunming mice.

Prevention and Treatment of Chinese Herbal Preparation Yinqiaotiangan against Pathologic Model of Streptococcus suis Serotype II in Kunming Mice

[ Objectlve] This study aimed to investigate the antimicrobial effect of Chinese herbal preparation Yinqiaotiangan against Streptococcus suis serotype II in vivo. [ Method ] The prevention and treatment tests were conducted with Kunming mice weighing about 18 -22 g. In the prevention test, Kunming mice were inocu- lated with Streptococcus suis serotype II and simultaneously taken orally 0.5, 1.0 and 2.0 g/ml Chinese herbal preparation Yinqiaotiangan respectively for continu- ous 3 d, once a day; the incidence rate, mortality rate and protective rate were detected after 7 d. In the treatment test, Kunming mice were inoculated with Strepto- coccus suis serotype II to establish the Streptococcus suis serotype II pathogenic model, and then taken orally 0.5, 1.0 and 2.0 g/ml Chinese herbal preparation Yin- qiaotiangan respectively for continuous 3 d, twice a day; the mortality rate, cure rate and effective rate were detected after 7 d. [ Result ] Results of the prevention test showed that the protective rate in experimental groups was extremely significantly higher than that in control group （P 〈0.01 ）, while the incidence rate and mortality rate were extremely significantly lower than that in control group （P 〈0.01 ）. Results of the treatment test showed that the incidence rate in experimental groups was extremely significantly lower than that in control group （P 〈0.01 ）, the cure rate in 0.5 g/ml group was extremely significantly higher than that in 1.0 g/ml group and 2.0 g/ml group （P 〈 0.01 ）, the effective rate in 0.5 g/ml group was significantly higher than that in 1.0 g/ml group and 2.0 g/ml group （ P 〈 0.05 ）, with no significant difference from the positive group （P 〉 0.05 ）. [ Conclusion ] The pathologic model of Streptococcus su/s serotype II could be effec- tively prevented and treated by oral intake of low dose of Chinese herbal preparation Yinqiaotiangan in Kunming mice.