33. Factors Influencing Animal Research

consider factors inherent to the animal itself (genotype, etc)

Intrinsic factors

consider factors that are external to the animal that may influence the animal's response

Extrinsic factors

chemical substance found within an organism that is not naturally produced or expected to be present within the organism. It can also cover substances that are present in much higher concentrations than are usual

xenobiotic

What are ACI rats models for?

-prostate Adenocarcinoma

-estrogen induced mammary carcinoma

What is the hepatic detoxification capability difference between Sprague Dawley female versus male rats? Why? This is not observed in what rat strain?

SD females reduced vs SD males hepatic detoxification capacity

reduced expression of NAD(P)H:quinone oxidoreductase

ACI (August Copenhagen X Irish)

Male or Female rats have greater expression of cytochrome P450 isoenzyme CYP2C11

male

trauma induced blood loss causes immunosuppression in male or female mice?

male

Outbred Swiss mice fed high saturated fats and low carbs produce more ________ offspring

male

What vitamins are involved in cytochrome P450 regulation. A deficiency in them decreases rate of what?

C, E, B complex

xenobiotic biotransformation

What impact do Dietary restrictions have?

Resists aging effects

Resist degeneration and infectious disease, neoplasia, and toxicity to chemical agents.

The central clock is located in the ____. The peripheral clock is in the ____.

suprachiasmatic nuclei

metabolic tissues (liver, pancreas, intestine)

Hormones produced by 8 endocrine glands

Pituitary, pineal, thyroid, parathyroid, adrenal, thymus, pancreas, gonads.

What organs are endocrine cells located in ?

 hypothalamus, duodenum, stomach, liver, kidney, hear, skin, adipose, placenta

What does Gonadectomy impact in ferret?

• Increases incidence of estrogen-secreting tumors in ferrets

• reduces stress assoc ACH release in hippocampus

• alters body composition

• ↓ growth hormone secretion

• ↓ incidence of hypertension and chronic renal dz

• ↓ cognitive performance and memory

• ↓ food intake in male rodents and ↑ food intake in females

What do orchiectomy and ovariectomy have in rodents? - stopped here

Male - orchiectomy decreases food intake

Female - ovariectomy increases food intake

temperature range in which homeotherms exert minimal energy to maintain core body temperature. (subject to minimal thermal stress)

Thermal neutral zone (TNZ)

Mice housed at TNZ had _________ tumor volumes and ________ post-implantation growth, fewer metastases, and __________ % of tumor free animals

reduced

delayed

increased

How does water temperature affect the sex of zebrafish offspring?

low temps = more males

higher temps = more females

Sendai virus transmission is ___ at high RH where influenza is _____

increased

decreased

Rats consume ___ more at higher RH

5%

Lowest viability of pathogenic microorganisms is when the room humidity is ____

50%

Increased temperature and RH generally ________ absorption of topicals by altering evaporative rates, peripheral circulation and viscosity of topical agent

increases

Humidity has a dramatic impact on intra-cage __________levels

ammonia

Rat ringtail incidence increases at RH below____% when the temperature is _____ TNZ

25; below

Mouse breathes approximately ____L of air per day under normal conditions

35L

Aromatic hydrocarbons released from cedar and pine bedding induce _____________

hepatic microsomal enzymes

Static caging significantly impedes air exchange, ⇧______ and ⇧_______

NH3 and CO2

Ammonia (NH3) formed by ____________ bacteria, or bedding with urealytic and urease activating enzymes (convert urea in urine and feces to NH3)

urease-producing

Microenvironmental NH3 can reach ____ppm in ____ days when mice are housed at maximum "Guide" capacity.

350 ppm

7 days

increased NH3 in mouse cages causes what in animals?

decreased cilia in lungs & increased chance of mycoplasma pneumonia

Pneumocystis has been attributed to elevated NH3

Ammonia limit - American Conference of Governmental Industrial Hygienists (ACGIH) established human exposure in the workplace limits. What is it?

25ppm over 8 hour time-weighted average

What is the CO2 limit set by ACGIH?

5000ppm as an 8hr TWA

Microenvironmental O2 can decrease by ___ in IVC caging compared to open cages with wire bar lids

0.5%

IVC mice had what changed to their bloodwork in comparison to open cages with wire bar lids

↑PLT, ↑RBC, ↑HCT and ↑HGB and lower WBC

What is the hearing range of lab animal? Humans? Rodent peak sensitivity?

Dogs, cats, rodents, small primates = Ultrasonic sounds (>20 kHz, hearing range of lab animals)

Human ear ~2 kHz

Rodents peak sensitivity 30 - 60 kHz

What things do low frequency sounds (<20kHz) alter?

water consumption, BP, blood corticosteroid, glucose/insulin, concentration

What are the impacts for noise in lab animal facility?

Excessive levels can induce adrenal and cardiac hypertrophy and hypertension in rodents reduces fertility, cause diuresis, increases urinary Na secretion, induce audiogenic seizures, reduce locomotor activity, and destroys ear structures

Audiogenic seizures (models for epilepsy) - animal species and specific mouse strains

• mice, rats, gerbils

• AKR, BALB/c, CBA, 129, SJL, RF, DBA/2, FVB, LP, SM

• Weanlings of any strain may be made susceptible if audio-conditioned b/w 15 and 21 days - may remain up to several months

Noise level guidelines per the ACGIH

<85dBA per 8hr TWA

Genetically epileptic prone rat (GEPR) /3 - sensitive to sound at approximately _____ days of age with subsequent audiogenic-induced seizure development

15

Genetically epileptic prone rat (GEPR) /9: sensitive to sound at _____ days of age- greater severity of signs

21

Lux below ___ will cause increased anestrus in hamsters

15

rat fecundity rates are highest at ____ lux

250

Recommendation at cage level: between _____ lux to prevent photoreceptor degeneration in sensitive species

130-325

Recommended lux level for sheep

220

Phototoxic retinopathy occurs especially in ____ rodents

albinos

Light cycle of __L:__D often used for rodent and zebrafish breeding

14L:10D

Contamination with as little as ____lux light exposure during the dark phase of the light cycle can reset the circadian rhythm in rodents

0.2

3 multiple choice options

lux exposure during the dark cycle can cause what?

increase growth of Morris hepatoma, NMU (N-nitrosomethylurea) induced mammary tumors, and human xenografted MCF-7 Cells

Exposure to __ lux during dark phase may increase depressive like responses and brain derived neurotrophic factor expression and impair cognition in rodents.

5

Continuous light over stimulates _________, leading to cessation of cycling, permanent vaginal cornification, and excess ovarian follicles in rodents.

reproduction

Zebrafish have what affects based on changing of the light cycle

gene expression, locomotion, repro cycle (not fin length)

What does each level of UV light do?

• UVA (320-400 nm)

• UVB (280-320 nm)

• UVC (100-280 nm)

• UVA (320-400 nm) – alters leukocyte and platelet counts

• UVB (280-320 nm) – disrupts DNA; can cause ocular damage, immunosuppression, immune modulation, and neoplasia

• UVC (100-280 nm) – germicidal

UV radiation in lab animals causes what?

neoplasia

result of rays and particles producing enough energy to release free electrons and atoms, leaving the atom electrically charged or ionized

ionizing radiation

________ is an endocrine disrupter and is a principal component of many thermoplastics used in rodent cages. What does it do in human breast cancer cells and animals?

Bisphenol A

Causes meiotic chromosomal abnormalities and proliferation of human breast cancer cells

Causes neuroendocrine and behavioral alterations for up to 4 generations

Relocation of mice and rats to clean cages increased heart rate, blood pressure, and activity for 105 minutes after change

Therefore recommended ___________hr acclimation after cage change for cardiovascular study

2

Wire caging is associated with increased incidence and severity of ____ syndrome in AKR mice

urologic

one or more of the following features: bladder distension; peripreputial urine staining, alopecia, and edema; paraphimosis; urethral blockage; ulcerative balanophosthitis; hydronephrosis; pyelonephritis; rectal prolapse; and perineal ulcerative dermatitis

mouse urologic syndrome (MUS)

Hardwood and pine shavings contain _________ derivatives that impede mating, and cause acyclicity in male and female rats.

linoleic acid

What other abnormalities can hardwood bedding cause?

alter core body temperature, alter baseline & cyclic AMP stimulated rates of acidification of rat liver endosomes, fungal spores, increase number of peyer’s  patches & IgA production, impede intercage ammonia

Corncob bedding has ____ disruptors which impede mating and cause cycle acyclicity and stimulate positive and negative breast and prostate cancer cell lines

corncob

Corncob bedding stimulates __________receptor-positive and negative breast and prostate cancer cell lines and prostate cancer xenografts

estrogen

IVC caging can cause _____ in neonates and hairless

chilling and dehydrating

Air moving at what rate causes a cooling effect

20◦C moving at 6 linear feet/min has 7◦C cooling effect

Vibrations near the resonance frequency (RF) are perceived (more or less) strongly and cause greater adverse effects

more

Vibration was highest at ___ frequencies and decreased as frequency increased to ___ hz.

low

12.5hz

Construction vibration can cause what adverse effects?

• Decreased food consumption, lower body weights, increased stillbirths, increase pup mortality

• Disrupted lateral line hairs of Xenopus = noxious feeding, regurgitation, stomach eversion, suffocation

Risk of continuous long term exposure to vibration should be considered when using ___ caging systems

ventilated

Aside from mice, low frequency vibrations can also impact ____

embryos of zebrafish

What is the most common source of xenobiotic exposure?

diet

What are some common xenobiotics in the diet?

Chlorinated hydrocarbons, organophosphates, polychlorinated biphenyls, heavy metals, mycotoxins, nitrates, nitrosamines, and estrogenic compounds.

________ diets commonly used to avoid contaminants

Certified

 (isoflavonoids & coumestans) in natural plant-based diets shown to have significant impacts

phytoestrogens

What are two common contaminant source of Natural plant-based diets (i.e. phytoestrogens)?

Alfalfa and soybean

What reduces concentrations of heat-labile dietary constituents (vitamins) and must supplement them in autoclavable diets?

steam sterilization

Autoclaving the standard rodent diet increases ___ by 14x. It is a neurotoxin and carcinogen.

acrylamide

Acrylimade can

What is Genistein?

Genistein is a soy-derived isoflavone and phytoestrogen with antineoplastic activity. Genistein binds to and inhibits protein-tyrosine kinase, thereby disrupting signal transduction and inducing cell differentiation.

Name some Heat labile vitamins

thiamin (B1), Vits A and E, pantothenic acid (B5), pyridoxine (B6), Cobalamin (B12)

Autoclaving increases ________ (neurotoxin and carcinogenic)

acrylamide

Gamma irradiated dry cat feed resulted in decreased vitamin ____ and elevated _________ concentrations

Induced leukoencephalomyelopathy in cats

A; peroxide

Hypervitaminosis ____ associated with teratogenic effects in rabbits (stillbirth, abortions, resorption)

A

3 multiple choice options

Deficiencies in calcium, copper, iron, magnesium, and zinc have been shown to _______ cytochrome P450

decrease

1 multiple choice option

Diets high in _______ can lead to hepatic hemosiderosis and death in the common marmoset (Callithrix jacchus)

iron

Exposure of rats to _________ water (pH __) leads to extensive enamel and dental erosion of molar teeth

acidified; pH2.0

Autoclaved glass water bottles containing acidified water - documented increases in ________ and formation of _______ crystals

Silica-containing compounds can induce ______ lesions in Guinea Pigs

silicon; silicon; renal

Rats exposed to 1 MAC sevoflurane

altered brain protein-level expression 28 days postexposure.

Tribromoethanol (Avertin), Xylazine, and Ket/Xylazine

Induce tissue injury (pulmonary parenchymal damage, muscle necrosis, peritonitis, corneal calcium deposition, and KCS-keratoconjuntivitis sicca )

Methoxyflurane

nephrotoxic to F344 rats - dose related diabetes insipidus

Desflurane, enflurane, halothane, isoflurane

Hepatotoxic

Compound A (degradant of Sevoflurane + CO2 absorbent) - Nephrotoxic to ____and _____

Rats and NHPs

Buprenorphine during gestation

Microphthalmia 8x increase

high doses of Buprenorphine

Pica in Rats

Barbiturates and Xylazine

Induce cytochrome P450 which can influence metabolism of other compounds

Topical benzocaine

methemoglobinemia

Xylazine

lowers insulin concentrations and abolished rise in insulin in response to glucose administration

Most euthanasia techniques are unsuitable to maintain the integrity of enzymatically labile neurochemicals

_________is used to fix brain neurochemicals and metabolites in vivo while maintaining the brain’s anatomic integrity

microwave irradiation

Aminoglycosides

Nephrotoxic, ototoxic, negative ionotropic effects, neuromuscular blockade

Procaine

toxic to rabbits, guinea pigs, mice