Summary: Guinea pig pups born normally or preterm were lightly anaesthetised, connected to devices measuring heart activity and breathing, and wrapped in a temperature-controlling blanket. Their body temperature was either forcefully raised or dropped to a certain point, monitored via a rectal thermometer.

Procedure: Guinea pigs were obtained from a breeding unit, who were either born at term or prematurely by their labour being induced early (before 90% of pregnancy duration) through repeated injections to the mother. Preterm pups were specially cared for until they had “no dysfunctions”. Pups were about one month old at the time of the study. Six term-born and four preterm pups each were used in two treatments. All were lightly anaesthetised (so that “animals were responsive to pain”), needle electrodes were placed to measure their heart activity, other devices measured blood pressure, breathing and oxygen saturation. Probes were put onto the skin where the hair had been removed using hair removal cream. Their body temperature was also continuously measured via rectal thermometer, pushed 4cm past the anus, and on the skin in four places. In the first treatment group, the pups were wrapped in a temperature-controlling blanket, slowly heated to 44°C, and kept there until the pup’s body temperature rose to 41.5°C. In the second treatment group, the pups were wrapped in a temperature-controlling blanket, which was slowly cooled to 15°C, and kept there until the pup’s body temperature fell to 34°C. Both thresholds were picked after a pilot study, where one pup was heated and another cooled to the point of irreversible damage. They had to be killed.

Purpose: To develop an animal model for thermal stress and use it to design a reproducible method to measure body reactions to thermal stress. This guinea pig model is intended to study predisposition for cardiovascular disease, for example, due to preterm birth.

Source: Journal article

Year published: 2023

Summary: Female guinea pigs were mated; some were fed additional sugary water until birth. The pups were used for several glucose tolerance tests and X-rays. They were killed to sample blood and tissue.

Procedure: Young female guinea pigs were kept in individual cages and fed a standard diet. At six months old, they were mated before being returned to individual housing. From 12 weeks old, nine of the female guinea pigs were supplemented with 10% fructose water until they gave birth. Another ten females served as control. After delivery, mothers and pups received the standard diet without fructose supplements. Only two pups of each sex were kept per mother. All were weaned at 21 days old. The pups were fasted for 14 hours overnight at 21 days, 2 months and 4 months old for glucose tolerance tests. Following a baseline blood sample, they were given dextrose into their mouths, and more blood was taken eight times within 3 hours. After the first glucose test, some pups were killed to sample tissues. The remaining pups were also fasted for 14 hours and were then anaesthetised for X-rays. After the final 4-month glucose test, they were killed for sampling, too. The treatment of the mothers was covered in a different publication in 2020.

Purpose: To determine whether increased fructose intake could have long-term consequences on offspring health. Excess dietary fructose is a significant public health concern, yet little is known about its influence on offspring development and later-life disease when consumed excessively during pregnancy.

Source: Journal article

Year published: 2022

Summary: Pregnant guinea pigs were induced to give birth early, to test medication on their pups.

Procedure: Eighteen pregnant female guinea pigs were given injections to induce labour early on day 62 of a 69-day pregnancy. Ninety preterm pups were born, but 29 died within a week. The 61 surviving pups were injected with varying drug doses for 7 days. Another ten females carried their pregnancies to term, giving birth to 15 pups. All surviving preterm and term pups were killed and dissected.

Purpose: To investigate the effect of ganaxolone, a seizure medication, on brain development in preterm guinea pig pups.

Source: Journal article

Year published: 2022

Summary: Young guinea pigs were treated with different sedatives. Their heart rate and blood pressure were measured before and during each treatment.

Procedure: Twelve juvenile guinea pigs were given 4 injections of different sedatives, with 48 hours between injections. After each injection, and once while not sedated, the guinea pigs were given cardiovascular assessments by inserting needle electrodes into their skin, attaching blood pressure cuffs over their forelimbs and attaching laser probes to their skin with rings and tape. An additional 20 guinea pigs only had their blood pressure taken using blood pressure cuffs.

Purpose: To investigate the effectiveness of four different sedatives in juvenile guinea pigs and the effects of these sedatives on heart and breathing.

Source: Journal article

Year published: 2021

Summary: Guinea pigs were made to inhale anaesthetic gases. Different probes were inserted and attached to the animals to measure responses.

Procedure: Twelve Dunkin Hartley guinea pigs between 75 and 118 days old each underwent two separate procedures where they were made to inhale anaesthetic gas; one using isoflurane alone and one using isoflurane plus nitrous oxide. They were fitted with equipment including a needle electrode, laser probes and a rectal probe to monitor their physical responses while under anaesthesia, which lasted a total of 210 minutes for each procedure. Water was withheld during the procedure (water could impact the anaesthetic). 

Purpose: To compare the effects of anaesthesia on heart activity, breathing and thermal regulation in juvenile guinea pigs, using only isoflurane gas versus isoflurane plus nitrous oxide.

Source: Journal article

Year published: 2021

Summary: Guinea pigs were fed either normally or supplemented with fruit sugar before and during pregnancy until birth. Mothers and pups were tested for glucose tolerance.

Procedure: Nineteen virgin female Dunkin-Hartley guinea pigs were mated and fed either a control diet (10) or a diet with added fructose (9) from 60 days before mating until they gave birth. Litters were maintained at four pups per mother until 21 days old, when all pups were killed via anaesthetic overdose. The study used 28 pups and killed the remaining unspecified number of their siblings as "excess". During the 21 days, the pups and mothers underwent glucose tolerance tests and had multiple blood samples taken after fasting.

Purpose: To investigate how increased fructose in a diet before and during pregnancy affects the health of their offspring.

Source: Journal article

Year published: 2020

Summary: Guinea pigs were injected with sedatives, caffeine, and later meth. Under anaesthesia, their livers were cut out before they were killed.

Procedure: Eight less than one-year-old female guinea pigs were kept individually and treated in two groups. Each guinea pig was injected with low doses of a sedative and caffeine. Blood samples were taken from the ear 1, 2, 3, and 4 hours after the injection, which served as control data. Half of the guinea pigs were injected with saline solution a week later, the other half with crystal meth. This was done on three days, with one day in between. Eight hours after the last injection, each guinea pig was deeply anaesthetised and had her liver cut out for analysis. A blood sample was taken directly from her heart before injecting an anaesthetic overdose to kill her.

Purpose: To study the effect of methamphetamine on enzyme activity in fertile females. The hope was to refine predictions regarding drug use by pregnant people.

Source: Journal article

Year published: 2020

Summary: Pregnant guinea pigs were grouped to give birth normally or were induced early. The pups were put through behavioural tests and then killed for dissection.

Procedure: Pregnant guinea pigs were randomly grouped to give birth normally (day 69) or prematurely (day 62). The preterm mothers were injected with several different medications for two days to induce labour, and their pups were treated with oxygen, heating pads and supplements as long as needed. Pups who did not respond or did not gain weight were killed. Term-delivered pups did not receive any treatment. All pups were handled daily and taken from their mother on day 21 to a group pen. Behavioural tests were performed on day 25 (being in an open field alone and with another guinea pig). On day 28 (corrected day 28 for preterm pups), all were killed with an anesthetic overdose to dissect them. The fate of the mothers is not stated. The study noted a percentage of stillborn or excluded (and killed) pups of 13.6% for the term group and 30% for the preterm group.

Purpose: To determine the effects of preterm birth on the cerebellum development in the guinea pig as a model to study the impact of preterm birth on cognitive and behavioural abilities in children.

Source: Journal article

Year published: 2018

Summary: In the applied study, guinea pigs get cochlear implants after destroying their hearing with noise. Treatments are tested before they are killed.

Procedure: In the applied study, around 100 adult guinea pigs are used. Different groups get their hearing damaged with 30min of 16 kHz, 120dB noise. Two weeks later, dummy cochlear implants are surgically implanted, with some also getting nanoparticles with or without a test drug in different concentrations. The hearing function is measured several times, and some guinea pigs are killed each time for tissue samples. For another aim, guinea pigs are implanted and put under anaesthesia for MRI measurements several times for 4 weeks before being killed for tissue sampling. Mouse and rat pups, 3 to 6 days old, are killed to use their cochlear for in vitro experiments.

Purpose: To study the ongoing injury of the cochlear of the inner ear following different causes of damage (noise exposure, ototoxic drugs, insertion of a cochlear implant). Other studies aim to reduce the effect of surgical trauma from cochlear implants.

Source: AEC application we received via Official Information Act request (description of purpose and procedure taken from the application that was made to the relevant Animal Ethics Committee before the actual study)

Year approved: 2018

Summary: A range of animals is used to teach researchers handling and experimental methods.

Procedure: Guinea pigs, mice, rats, rabbits, pigeons, other birds, and sheep are used in various teaching scenarios, including euthanasia methods, restraint, blood sampling, drug administration, anaesthesia, handling and sexing, and basic surgical procedures.

Purpose: To teach researchers restraint methods, experimental techniques and procedures.

Source: AEC application we received via Official Information Act request (description of purpose and procedure taken from the application that was made to the relevant Animal Ethics Committee before the actual study)

Year approved: 2015