05a. Hamster biology and models

4 Features of a hamster

-large cheek pouches

-thick bodies w/ short tails

-excess loose skin

-incisors grow continuously

Why is it difficult to cross foster hamsters?

they are born with incisors

Dental formula of hamster

1-0-0-3

Latin name of the Syrian or Golden Hamster

Mesocricetus auratus

What are the characteristics of newborn hamsters?

-Altricial

-Born with incisors

-Only females have nipples

Natural environment of syrian/golden hamster (Mesocricetus auratus)?

-deep tunnels

-cool temps, high humidity

-nocturnal

Major differences between male and female syrian/golden hamster (Mesocricetus auratus)

-females larger

-males - prominent flank glands

syrian/golden hamster (Mesocricetus auratus) are radiosusceptible or radioresistant?

radioresistant

What is temperament of male versus female?

Males are more docile

When do ears open, hair growth, eyes open, wean date, and maturity date of syrian/golden hamster (Mesocricetus auratus)

-4-5d

-9d

-14-16d

-21d

-6-9wk

Average lifespan of hamster, how does it differ between the sexes?

-18-24mo

-shorter life span in females dependent on strain

What is the optimal time for teratogenic studies in syrian/golden hamster (Mesocricetus auratus)

8th day of pregnancy

number of digits on front and hind limbs

4 and 5

What is the recommended lighting and light cycle (breeding)?

Light 12-14h (14 hr for breeding)

325 lux 1 M off ground

What is the chromosome # of Mesocricetus auratus?

Diploid chromosome # = 44

What is the reproductive lifespan of Syrian hamster?

Starts 6-8 weeks

Goes until 14 months of age

What is the gestation period of Syrian hamster?

15-18 days

Usually 15.5 days: *shortest of all lab species*

Cheek pouches do not contain what? Do contain?

-gland cells

-mast cells

The cheek gland of a hamster are ____ meaning they lack intact lymphatic drainage pathway and will support transplanted foreign tissue without immunological rejection

immunologically privileged site

Due to the immunological privilege of the cheek pouches, hamsters are the best model for what?

human oral cancer development

manually everted cheek pouch in hamster

What can Syrian hamster's teeth use to study? Why?

-dental caries

-they are prone to them

What can influence the formation of dental caries in hamsters?

carbohydrate in diet

Hamster stomach has glandular and nonglandular portion. The nonglandular portion is similar to ruminants how?

-elevated pH amd ,icroflora contribute to fermentation

Intragastric administration of ____ predictably results in intraluminal accumulation of fluid in the small bowel, cecum, and proximal colon. Historically used to study ___ (multiple) that may inhibit intestinal fluid secretions

-cholera enterotoxin

-indomethacin, polymyxin B sulfate, glucose electrolyte solutions, and colchicine

How is the hamster, mouse, and rat pancreatic duct and bile duct different compared to humans

-major pancreatic duct joins common bile duct BEFORE it enters duodenum

-humans they enter at the same time

Hamsters can serve as a model for pancreatic carcinogenesis by inducing pancreatic tumors & metastatic pancreatic cancer via ___ administration of ___ or ____.

-SC

-nitrosamines or transplantable cell (PGHAM-1)

Why are syrian/golden hamsters a good model for chronic bronchitis?

-conductive airways w/ limited number of glandular structures

Why are syrian/golden hamsters good models for chemical carcinogenesis in resp system?

rarely develop spontaneous bronchiogenic and pulmonary cncers

Golden/syrian hamsters are also good models for long term smoke inhalation, why?

-resistant to pulmonary infection

-can decompose nicotone

Syrian/golden hamster kidneys are highly responsive to ____. Males given this develop renal tumors which make them a good model for human renal cancer.

-estrogen

Male syriang/golden hamster adrenal glands are 2X the size of females due to what?

greater number of reticular cells

Syrian/Golden hamsters where the first model for study of _____ adrenal necrosis

addisonian

Syrian/golden hamsters do not reject ____ to same extent as other models because immune system be weird

skin allografts

Which immunoglobulin doesn't hamster have? What other species lack this immunoglobulin?

-Got GAME (no IgD)

-rabbits and swine

____ is the first example of a hamster lambda light chain – uniquely costimulatory for gamma-delta T cells – may be relevant for studying treatment of gamma-delta T cell dysfunction-associated diseases such as chronic non-healing wounds and cancer

HL4E10 antibody

_____ are pigmented lacrimal glands that secrete a lipid and porphyrin rick material that lubricates the eyes

harderian glands

Syrian/golden hamster specifically have marked sexual dimorphism in regards to the harderian glands. What’s the difference?

-females secrete higher concentration of porphyrin

-androgen denependent and exhibitis seasonal variation

What do males use flank glands for? When do they produce secretions? What do they look like?

-scent marking

-in response to androgens

-look wet when sexually excited and may appear pruritic

flank glands in male syrian/golden hamster

At what temperature does Syrian hamster go into hibernation?

5C (+/- 2C)

-not extremely reliable - can’t use as model

Hibernation in syrian hamster is associated with desuration of what?

white adipose tissue

Syrian hamsters do not fatten prior to hibernation so you must do what to ensure they survive?

periodically wake them up

What hamster species is the true hibernator?

European hamster (Cricetus cricetus)

What diet can the syrian hamster be fed?

regular rodent diet

How much do adult syrian hamsters eat in a day? How much do they drink? Recommended protein in diet?

-10 to 15g per day

-30mL/day

-16%

What is necessary in syrian hamster diet?

-higher levels of zinc, copper, and potassium

-absolute need for Vit B and non nutritive bulk

What vitamin is essential in syrian hamsters for proventing myocytolysis in cardiomyopathic hamsters

vitimane E

How big should the slots be for Syrian hamster food? Alternatively hamsters can be fed how?

-Slots must be at least 7/16-inch wide (standard rodent is 5/16 wide)

-Feed directly on floor

What sipper tubes should be used with hamsters?

stainless steel only

hamsters are carprophagic or nag?

yes

hamster just living life

What drugs are Syrian hamster sensitive to? resistant to?

-Sensitive to corticosteroids, serotonin

-Resistant to histamine, morphine, phenobarbital, radiation

What antibiotics should be avoided in Syrian hamster? why?

-Avoid lincomycin, clindamycin, ampicillin, vancomycin, erythromycin, cephalosporins, gentamicin, penicillin

-Clostridum difficile overgrowth

Average weight and age of adult male vs female syrian hamster

-male - 90g, 6-8wk

-female - 90 to 100g, 8-12wk

When doe reproductive capacity decrease in hamsters?

14mo

Estrous cycle length of syrian hamster? how to tell they ovulated?

-4d cycle

-2d w/ copious vaginal discharge w/ distinct smell

How to breed syrian hamsters? When do you know it’s not successful?

-female introduced to male cage on 3rd day following post ovulatory discharge approx 1-2hr before start of dark cycle

-if receptive - lordosis with raised tail

-not breeding in 5m or female is aggresive to male

-REMOVE FEMALE NEXT DAY

Gestational length of syrian hamster? How long is parturition?

-16d - shortest of any LAM rodent

-3hr

Signs of parturition in female hamster?

abrupt change to maternal behavior, weight gain, abdominal distension by 10d

Litter size of hamster?

about 8 (4-12)

How long should you wait before handling litter or hamster?

-7-10d, cannibalization common

-cross fostering & bottle feeding difficult/unsuccessful

-transiently put babies in cheek pouches when stressed

What is Blandau test?

Female hamster assumes position of lordosis if ready to mate

How to know it’s pseudopregnancy in syrian hamster?

discharge seen on day 5-9

when are pups weaned in hamster? When does estrus resume?

-21-28d

-1 to 8d following parturition

How can diabetes be induced in syrian hamsters? What is this model used for?

-streptozotocin

-embryonic development in diabetic pregnant females

floor space requirement for hamster according to AWA and guide?

60g or less = 10in²

female w/ litter = 121in²

height must be 6in from cage floor to cage top

How many syrian hamsters housed in an enclosure?

mature animals housed separately bc they fight, esp females

What environmental enrichment is strongly recommended in hamsters?

-some sort of burrow or shelter enrichment

-nesting material recommended for both sexes because they both make nests

How deep should bedding be to reduce cage bar chewing?

40 to 80cm

Preferred substrate?

-pine shavings

-nesting material preferred over all bedding

how often should bedding be replaced

1 to 2 wk

Temp and humidity per the BLUE BOOK`

68-79F, 30-70%

How can you reduce aggresiveness in a hamster?

early handling

A startled or awakened hamster will do what/

roll on back and present to bite

If you need to grasp a hamster, how should you?

• Approach from behind, grasp around head & shoulders 

• Approach from behind, grasp only skin of thorax and abdomen, skin taut – animal lifted, hand rotated so animal rests in hand 

• Approach from head, thumb and forefinger grip base of tail, loss skin secured between fingers and palmar surface before lifting 

• Approach from head – enclose entire body w/ 1 hand, thumb placed on base of rear leg, first & second fingers on opposite side of base of tail, third and fourth finger reastrain head and forelimbs

how to properly restrain a hamster

Cheek pouch tumor model induced by _____  topical application to buccal pouch. Advantage of this method?

-7,12-dimethylbenz(a)anthracene (DMBA)

-predictable nature of tumor progression

Pancreatic ductal adenocarcinoma can be induced by?

SC nitrosamines (n-methyl-N-nitrosurea) or transplantable cell line PGHAM-1

Respiratory tract tumors can be induced in syrian hamsters by administration of what? What happens if it’s administered with hyperoxia?

-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)

-increases potential for free radical damage to DNA of lung

Upper airway tumors can be induced by what?

-wounding + n-methylnutrosourea

Which Simian virus can Syrian hamster be used to study?

-Simian vacuolating virus 40 (SV40)

-tumors developed depend on route of administration

100% of male hamsters will develop renal tumors when given this

exogenous estrogenic compounds

Hamsters are one of the few animal models that permits replication of the virus and thus they are a good model for use of ____ as a cancer therapeutic

human adenovirus

Cholesterol cholelithiasis can be induced by ____ or ____

-excess dietary cholesterol

-sucrose rich diet

Feeding _____ diet for 3wk will induce type 2 DM

streptozotocin (STZ), alloxan, high fat (15%) modest cholesterol (0.12%) diet

Feeding _____ leads to diabetes w/ nephropathy and coronary lesions

Albino-panda-albino (APA) strain of STZ

Hamsters are a useful model for human atherosclerosis because their lipid metabolism is similar to humans. ____ is the main plasma cholesterol carrier

LDL

HCM, DCM are inherited conditions, caused by a defect in the ____ gene. Lines that have this include ____ (multiple)

-sarcoglycan

-original polymyopathic line 1.50, BIO 82.62, BIO TO-2, BIO 53, and UMX-7.1

Leismania infantum causes polymyositis making hamsters a possible model for ____

inflammatory myopathy

Hamsters are natural hosts for what ABSL4 agent?

Hantavirus pumonary syndrome - Buynaviridae

Hamsters are used to study ____ against coronavirus

vaccine efficacy

Hamsters are a model for ____ tuberculosis

atypical

Hamsters can get CS similar to human with hemorrhagic typhlitis when given what? They are used as a model to test what?

-clindamycin followed by C. difficile

-human monoclonal antibodies to toxin A or B

COPD and emphysema can be induced via ____ or ___ in hamsters

-intratracheal porcine pancreatic elastase

-feeding copper deficienct diet

Human fertility can be assessed via the ____ assay which analyzes the ability of the sperm to penetrate the hamster oocyte

zona free hamster oocyte assay

What is the gestation period of Chinese hamster?

20.5 days

What are some characteristics of Chinese hamster? missing organ? temperament?

No gallbladder

Aggressive!

House singly

Hard to breed

retinal receptor- rod cells only

Females have four pairs of mammae.

Chinese hamster ovary (CHO) cells are used almost exclusively for cell culturing experiments to obtain heterologous protein products

What is the chromosome # of Cricetulus griseus?

Low chromosome diploid # (2n = 22)