Swimming Exercise Protocol and Care Methods for Pregnant Rats

Our research delineates rat breeding methods, prenatal swimming training procedures, and post-breeding nursing protocols for rats, which will be of good help to the researchers of excess physiology and the prenatal biology. As pregnancy progresses and the abdomen of the rat swells, treadmills and wheel-running exercises may cause repeated contact of the abdomen with hard surfaces. In contrast, the water environment in swimming exercise protocol provides buoyancy, reducing the risk of exercise-related injuries for pregnant animals.

Maternal obesity can lead to an increased incidence of cardiovascular and metabolic diseases in offspring. In the future, where we apply this swimming exercise protocol to high fat diet induced obese pregnant mice to explore the epigenetic mechanism and find a new way to curb the intergenerational inheritance of obesity related diseases. To begin, label the microscope slides with the date and identification details of the rat.

Between 18:00 and 19:00 PM, grasp the base of the female rat's tail with the thumb and forefinger while applying pressure from the other fingers onto the lumbar vertebra of the rat. To collect vaginal secretions, moisten the cotton swab with saline solution. After lifting the rat tail, insert the tip of the swab gently into the vagina and roll it.

Then roll the swab tip across the slide and locate the cells under the microscope using the 10x objective. After recording the estrus cycle stage, place the female rat along with a male rat in the mating cage between 19:00 to 20:00 PM.On the second day between 07:00 and 08:00 AM, if a copulatory plug is found at the base of the mating cage, examine the vaginal secretion smear of the female rat as demonstrated earlier. If pregnancy is confirmed, isolate the female rat in a separate cage.

On gestation day 20, replace the pregnant rat's cage with a clean one and place medical absorbent cotton in the cage. Supply sufficient water and food for seven days and position the cage in a quiet location. On the 21st day postpartum, distinguish the gender of the offspring rats.

In females, the distance between the anus and the external genitalia is shorter than it is for males. Place the male and female offspring in two separate cages. To begin, obtain female rats for adaptation training.

Then grasp the tip of the rat's tail, lift it, and place the rat in a circular bucket filled with water. Throughout the 15-minute adaptation training, monitor the water temperature every five minutes and add warm water to maintain the temperature. After the training, wash the rat fur in clean water, tempered at approximately 34 C.and transfer the rat to a cage with towels.

Using a hand dryer, dry its fur thoroughly. Weigh the pregnant rat every day before training. For swimming training sessions, place the rat in water, taken in a circular bucket and let it swim while maintaining the water temperature at about 34 C.Following the exercise, dry the rat, and provide it with 5 g of rodent sunflower seeds as a nutritional supplement.

Thoroughly clean and disinfect all equipment with ultraviolet light, including water buckets and towels. To begin, obtain a swim-trained euthanized pregnant rat. Using a surgical knife, make an incision in the lower abdomen to expose the uterus completely.

With forceps and scissors, carefully open the uterus to reveal the fetuses and placentas. Gently peel away the surrounding amnion, preventing any harm to the fetuses. Sequentially separate fetuses and placentas by their anatomical positions.

Using sterile gauze, clean the fetus to eliminate any blood and mucus. Then weigh the fetus and the placenta. Next, observe the distance between the anus and genitalia and document the gender as well as the total number of male and female fetuses.

Unfold the curled up fetus and using a caliper, measure the length while the fetus is lying flat.