Lewis

Inbred

Lewis Inbred Rat Model
This line is cryopreserved and requires cryorecovery.

  • Model #
  • Genotype
  • Nomenclature
  • LEWIS-F
    LEW/MolTac
  • LEWIS-M
    LEW/MolTac
  • Commonly used in immunological studies and to produce autoimmune models
  • Used in diabetes research due to high susceptibility for induction of Insulin Dependent Diabetes Mellitus (IDDM) by streptozotocin

Origin:

Developed by Wistar Institute in the 1940s/1950s. Taconic's substrain can be traced originally to Scripps Clinic, La Jolla, to University of Pennsylvania to Simonsen Laboratories in 1966, to Institute of Pathological Anatomy, University of Copenhagen, Denmark 1973. From University of Copenhagen to M&B A/S (now Taconic Europe) in 1977. Inbreeding F(+) 101 (February 2002). Rederived Taconic US in 2002. The Taconic US foundation colony was at F16 in 2005.


Availability:

Available for immediate cryorecovery

Genetics:

  • Strain Profile: Aco1b, Amy2a, Anpepb, Es1b, Es2a, Es3a, Es4b, Es6b, Esda, Fh1a, Hbba, Pepca
  • Immunology: RT1-Al, RT2a, RT3a

Color:

Albino

Species:

Rat



n= 100 per sex at MPF health standard from US production colonies. Data collected 2012-14.
High and Low represent mean +/- 2 standard deviation.
Based on sample size the charts above represents ~90% of the population.
All growth curves represent animals housed in our barriers, at our standard density and fed NIH31-M diet. Variations at customer facilities will alter expected growth curves.
Growth charts are provided only as a guide, if a specific weight criteria is needed please order animals by weight.

Customize this chart by clicking the legend elements, then explore download options by hovering your cursor over the down arrow to the right of the chart title.
Average litter size: 7
Lewis Rat Physiological Data Summary (July 2003; N=10/group):

Parameter Units Lewis Rat Males Lewis Rat Females
Serum Chemistry Avg ± S.D.    
Calcium mg/dL 12.0 ± 0.3 11.7 ± 0.2
Phosphorous mg/dL 12.5 ± 1.4 10.7 ± 1.3
Glucose mg/dL 88 ± 15 87 ± 5
Creatinine mg/dL 0.3 ± 0.1 0.3 ± 0.1
BUN mg/dL 10 ± 1 11 ± 2
Total Bilirubin mg/dL 0.1 ± 0.0 0.1 ± 0.0
ALK U/L 269 ± 30 148 ± 18
ALT U/L U/L 36 ± 26 36 ± 59
Total Protein g/dL 6.5 ± 0.3 6.0 ± 0.3
Blood Counts
Erythron      
Red Blood Cells X10^6/uL 7.9675 ± 0.3582 7.813333 ± 0.426146
Nucleated RBC X10^6/uL 0 ± 0 0 ± 0
Hemoglobin g/dL 14.6 ± 0.5 14.6 ± 0.8
Hematocrit % 48.0 ± 1.6 48.0 ± 2.7
MCV fL 60 ± 1 62 ± 1
MCH pG 18.4 ± 0.4 18.6 ± 0.2
MCHC % 30.5 ± 0.2 30.3 ± 0.2
Platelets      
Platelets X10^3/uL 766 ± 109 849 ± 89
Leukogram      
White Blood Cells x10^3/uL 7.52 ± 1.87 6.522222 ± 2.310313
Neutrophil x10^3/uL 0.531 ± 0.207 0.944 ± 0.518
Bands x10^3/uL 0 ± 0 0 ± 0
Lymphocyte x10^3/uL 6.916 ± 1.924 5.447 ± 2.003
Monocytes x10^3/uL 0.067 ± 0.069 0.090 ± 0.101
Eosinophil x10^3/uL 0.005 ± 0.015 0.040 ± 0.049
Basophils x10^3/uL 0 ± 0 0 ± 0
Others x10^3/uL 0 ± 0 0 ± 0
Organ Weights      
Stomach g 1.184 ± 0.212 1.032 ± 0.116
Ileum g 3.929 ± 0.558 3.603 ± 0.420
Colon g 0.900 ± 0.171 0.721 ± 0.210
Lungs g 1.857 ± 0.271 1.423 ± 0.309
Heart g 1.127 ± 0.127 0.952 ± 0.211
Liver g 9.303 ± 1.136 7.278 ± 1.029
Spleen/Pancreas g 1.277 ± 0.197 1.032 ± 0.092
Kidney (L) g 1.042 ± 0.139 0.818 ± 0.075
Kidney (R) g 1.068 ± 0.131 0.850 ± 0.097
Testes (L) g 1.133 ± 0.127 -
Testes (R) g 1.127 ± 0.119 -
Ovary (L) g - 0.066 ± 0.013
Ovary (R) g - 0.068 ± 0.019
Urinalysis      
Glucose mg/dL Neg. Neg.
Blood - Neg. Neg.
Ph - 8.00 ± 0.24 7.30 ± 0.42
Protein mg/dL N/A N/A
Specific Gravity - 1.01 ± 0.00 1.01 ± 0.00

Phenotyping Procedures:

Animal Receipt and Maintenance

A quantity of twenty rats (ten males and ten females) was submitted for testing, strain identified as Line Lewis Rat (Lew/MolTac), age 7 weeks. Rats were received at RBU 3, Taconic Biotechnology, Albany NY and acclimated for three days on irradiated NIH #31M rodent diet and sterilized water ad lib, sterile contact bedding (paper chip) and a 12:12 light:dark cycle. All animals appeared normal during this period and routine health surveillance of this colony detected no microbial pathogens. Rats were assigned study unique identification numbers (males 1-10, females 11-20).

 

Urinalysis

All rats were fasted in metabolic cages and an overnight urine sample was collected. Urine analysis was performed using Multistix 10 SG (Bayer). Strips were read and recorded as per the manufacturer's instructions, and the results are presented in Table 2.

 

Clinical Chemistry and Hematology

A terminal blood sample was taken from Carbon Dioxide - anesthetized rats via cardiac puncture. The collected blood was divided into two samples. One sample was treated with EDTA and stored at 4°C for hematological evaluation. Another sample was allowed to clot at 4°C for 30 minutes, and then centrifuged at 7000rpm for 10 minutes, and the serum was decanted and frozen at -80°C for clinical chemistry analysis. A slide smear was made from a single drop of whole blood. Frozen serum, chilled whole blood, and slides were delivered to LabCorp (RTP, NC) for analysis; the results are presented in Table 3. Unless otherwise indicated, serum chemistry data is generated from a Hitachi 717 automated analyzer and hematological data is generated from a Celldyne 3500. WBC differential counts are performed manually.

 

Necropsy and Organ Weights

All rats were euthanized and bodyweights were recorded. Representative tissues were collected, weighed, and immersion fixed in 10% Neutral Buffered Formalin. Tissues were delivered to the Taconic lab for histological preparation and evaluation. Tabulation of organ weights is presented in Table 4. The pathologist's summary and detailed histological descriptions follow.

 

Discussion

All animals were thrifty on arrival and appeared clinically normal. Locomotor behavior was normal and there were no visible lesions or discharges at the mucous membranes. All tissues appeared normal on gross necropsy evaluation and weights were within normal limits. There were no unusual findings upon collection of these tissues nor otherwise observed in the body cavities.

The overall profile of these rats is consistent with expectations of a general-purpose rat. None of the parameters are indicative of impaired system function.