Summary: Transgenic mice who carried the desired gene defect were mated. Pregnant mice were killed 12, 15, and 18 days into pregnancy. The unborn babies were taken, skinned, and gutted, with their skeletons stained for better pictures.

Procedure: A mouse line developed in Australia was used for this experiment. They can only use animals who carry the desired gene defect but don’t develop it (this is called heterozygous). The gene expression leads to them dying as soon as they’re born. So transgenic carriers were mated, and pregnant mice were killed 12, 15, and 18 days into the pregnancy by breaking their neck. The embryos were taken, skinned and gutted before the rest of the soft tissue was dissolved in acetone and washed away with alcohol. The skeleton was stained to then take pictures.

Purpose: To further research the genetic causes of scoliosis. They hoped for insight and an animal model for future studies into understanding Adolescent Idiopathic Scoliosis (AIS).

Source: Journal article

Year published: 2022

Summary: Transgenic mice were bred to have diabetes symptoms. Together with control mice, they were fed a normal or a high caloric diet and compared for their fertility over 150 days.

Procedure: Transgenic mice were bred to miss a specific regulator in the brain for leptin and insulin. Male and female mice were used and fed either a standard diet or a diet containing much more calories. Their fertility was monitored over 150 days.
(We only have the abstract available for now and will provide more details once available.)

Purpose: To study the regulation of leptin and insulin signalling and how that influences obesity and fertility. Both are important to regulate blood sugar levels and fat tissue build-up and are involved in diabetes.

Source: Journal article

Year published: 2022

Summary: Mice were squeezed into plastic cones, and different test drugs were dripped on their nose. They were then anaesthetised, fixated, and a stroke was caused by injecting a chemical into their brain. Before and after, mice had to walk over mesh wire and were trapped in a glass cylinder for tests. All were then killed to take their brains.

Procedure: Male mice were restrained in small plastic cones with the tip cut off to drip the new drugs onto their nose. Stroke was provoked in anaesthetised mice in a stereotaxic frame. The skull was opened, and Rose Bengal was injected. This compound clogs when hit with light. A bright light was directed at the skull for 15min, and the skin was closed with surgical glue. Behaviour was tested one week before and after surgery in two ways.
1) Grid-walking consisted of a wire mesh where the mouse was videotaped walking around for 5min to count the “stepping errors”.
2) In the Cylinder task, the mouse was put into a cylinder to count the use of left and right forefoot when they looked up.
Ultimately, all mice were anaesthetised, their hearts flushed with paraformaldehyde, and their brains taken to measure the stroke size.

Purpose: To test the potential of specific fatty acids (PUFAs) as a stroke medicine. Some potential of PUFAs to protect brain neurons is known, but they can also cause inflammation.

Source: Journal article

Year published: 2022

Summary: Mice were operated on several times. They were made to experience an artificial stroke, were later injected with a possible treatment, and then were injected with a marker. The mice had their memory tested before they were killed by having their hearts flushed with paraformaldehyde.

Procedure: Anaesthetised male mice were placed in a stereotaxic frame. Their skull was exposed, and Rose Bengal (a compound that clogs when hit with light) or control solution was injected. The skull was hit with light for 22min. They were anaesthetised five days later and placed in the stereotaxic frame again. Mini pumps with the test drugs were inserted between the shoulder blades under the skin, and a human protein or control solution was injected into the stroke region of the brain. Three days after this surgery, object recognition was tested with objects in a light, open area. The behaviour of the mice was monitored. 30 days later, the animals had to complete the test again before another surgery. This time, a tracer was injected into the brain, and the skin was closed with surgical glue. Five days later, 35 days after the artificial stroke, all mice were anaesthetised, their hearts flushed with paraformaldehyde, and their brains were dissected so that the size of the stroke could be measured. 

Purpose: To test the potential of new stroke medicine, with and without adding a human-own protein. This protein, called rhBDNF, seems to play a role in stroke recovery.

Source: Journal article

Year published: 2022

Summary: Mice were anaesthetised, and their prostate was injected with cancer cells or a control solution. A 42-day treatment course started three weeks later with different treatment drugs and control solutions. In the end, all mice were killed.

Procedure: Mice were imported from Australia at 9 weeks old and housed in sterile conditions with access to food and water. They were anaesthetised and received pain medication before an incision was made above the penis. Either prostate cancer cells or a control medium was injected near the prostate, and the incision was sutured. Three weeks after surgery, mice were randomly assigned to one of three treatment options or a control solution. Mice were force-fed daily for 42 days and then killed with CO2. Blood samples were taken, and the prostate was dissected.

Purpose: To test the potential of new cancer drugs against androgen receptor castration-resistant prostate cancer. This cancer currently has no clinically approved targeted treatment option.

Source: Journal article

Year published: 2022

Summary: Mice were trained to eat jelly and were then operated on so that they would experience an artificial heart attack. They received either a new treatment drug or a control substance for 2 weeks. Heart ultrasounds were performed before and after surgery and at the end of treatment. Then they were killed and dissected.

Procedure: Study number 3 of this paper was conducted at Otago University: Female 8-week-old mice were kept alone to measure how much they ate. The mice were trained to eat jelly for 5 days before surgery. They were anaesthetised, the chest was opened, and one of the arteries supplying the heart walls was sutured to mimic a heart attack. They were allowed to recover for three days with pain killers and antibiotic medication before starting the treatment test. They received jelly with the test drug or control solution for 14 days. Echocardiography (ECG) measurements were performed at the beginning as a baseline, after the surgery, and after 14 days of treatment. Following the last measurement under anaesthesia, the heart was stopped by injecting salt solution and then flushed with paraformaldehyde. Tissue was collected.

Purpose: To test a potential heart attack treatment. The drug is supposed to make new blood vessels around the infarction. The tests were separated into 3 studies, 2 of them done overseas (transferring human cells into mice and safety testing the drug on healthy mice). The third study was done in NZ to test the drug on mice with a heart attack.

Source: Journal article

Year published: 2022

Summary: Transgenic mice were implanted with a capsule containing either hormones or not. Vaginal smears were done for several weeks, and serial blood tests (where blood was collected every 6min for 2 hours) were performed twice. In the end, all mice were killed.

Procedure: Female transgenic mice were anaesthetised. A hormone capsule or control capsule was pushed through an incision between the shoulder blades, and the cut was sutured. For 90 days, mice were weighed weekly, and from 8 weeks after surgery, they were trained for blood sampling. For the last 21 days, vaginal smears were performed (not stated, but most likely daily). Two sets of serial blood collection were done two weeks apart. Here, blood was collected every 6min for 2 hours from a small incision in the tail-tip. After 90 days, all mice were killed by anaesthetic overdose, and their hearts were flushed with paraformaldehyde.

Purpose: To research the causes of polycystic ovary syndrome (PCOS). This condition is estimated to affect 10% of people with active ovaries. It involves ovary cysts, disturbances in ovulation and hormonal problems.

Source: Journal article

Year published: 2022

Summary: Mice were genetically modified to show autism-like symptoms. Together with control animals, they were either fed normally or with a high-zinc diet. Behavioural tests were performed, including playing loud noises and giving them electrical shocks. At least some, likely all, were killed.

Procedure: Male transgenic mice were imported from Taiwan and bred to wild-type mice. DNA samples were taken from the babies via ear punch, and they were weaned at 21 days. They were then housed in groups and randomly assigned to a control or zinc-enriched diet for 6 to 8 weeks. Behaviour experiments were performed at 9–11 weeks of age on male and female mice on either diet. The tests were:
Grooming behaviour (recorded for 30min under red light in an unfamiliar arena); moving from a dark to a light test chamber; social interaction between unfamiliar mice in a test chamber.
Another group was used for Auditory fear conditioning. The mouse was placed in an operant chamber with constant 60dB white noise. After 4min of acclimatisation, three loud noises were played (80dB for 18 seconds), followed by an electric shock from the floor (0.6mA, 2 seconds). The next day, the mouse was brought to the same chamber, and forty of the loud tones were played for 20 seconds, each with 5-second breaks. Freezing in fear of a shock was measured. Mice were killed with CO2 and decapitated.

Purpose: To test zinc supplements as a treatment for Autism Spectrum Disorder (ASD). Zinc deficiency seems to be a risk factor, and there are indications it might “normalise impaired social behaviours”. But this has only been shown in animal models so far.

Source: Journal article

Year published: 2022

Summary: Mice were anaesthetised, and their body composition was measured several times. Their grip strength and balance were tested with lab equipment. In the end, all were killed.

Procedure: Transgenic mice were anaesthetised, and their body composition was measured with either magnetic resonance imaging (MRI) or a densitometer (density of fat and muscle are different). Their grip strength was measured with a special device. Balance/coordination was tested by having them balance on a rotating drum. All animals were killed at around 21.5 months old so that their tissue and blood serum could be examined. 

Purpose: To try and prove that a specific gene is influencing the build-up of body fat. They examined the body composition in a cohort of young Māori and Pacific men and in two mouse models where this gene was implanted into their DNA.

Source: Journal article

Year published: 2022

Summary: Transgenic mice were anaesthetised, and a blood vessel in their brain was blocked to simulate a stroke. They then received either a test drug or a control solution. After recovery, their food was limited to test their fine motor skills in a special lab instrument every other week. After two months, they were killed.

Procedure: Transgenic mice were imported from Australia and bred. Mice were anaesthetised, and a brain artery was blocked for 45min to simulate a stroke. The head was sutured, and mice received pain medication for three days in their drinking water. From then on, mice received daily injections of either the test drug or just saline for 28 days. Animals were checked weekly for general condition, joint and overall mobility characteristics. Food was limited to 4 hours per day for the staircase test (before surgery as a baseline, and after surgery as a treatment test, 2, 3, 5, 7 and 9 weeks after surgery). In daily 10-min trials, the mice were placed on an elevated narrow platform, with tiny staircases leading down on either side. Food pellets were placed on each step. The total number of pellets collected on each side measured sensory capacities and coordination. Sixty-three days after stroke surgery, animals were anaesthetised and killed by flushing their hearts with paraformaldehyde.

Purpose: To test if a drug (citalopram) improves fine motor skills after a stroke. The transgenic mouse line used is made so that their immune cells are green fluorescent, which makes it possible to monitor inflammation in the brain. Therefore, they are used as an animal model for stroke.

Source: Journal article

Year published: 2022