This study aimed to describe the use of trans-abdominal ultrasonography for pregnancy diagnosis and fetal age estimation in golden hamster. It seems that pregnancy diagnosis and aging is difficult in hamster due to some specific stress responses during restraint. To the best of our knowledge, ultrasound has not been used to diagnose pregnancy in hamster. Injection of 5 IU of eCG and hCG and mating 18 h after hCG provided appropriate results in superovulated golden hamsters. PMSG (eCG) and hCG are the common hormones in these protocols. ĭifferent doses and timings have been evaluated for estrous synchronization and superovulation in hamster. The vagina has two lateral pouches that must be distinguished from vaginal canal for sampling and staging of estrous cycle. The cranial part of cervix composes of two canals and extends to duplex uterus. The anatomy of reproductive tract has unique features in hamsters in comparison to other rodent species. Increased vaginal discharge, especially on the third day, is a sign of estrus. The female can then be placed in a male cage for mating. Single mating requires an accurate diagnosis of estrus. Female hamsters kept in the same group tend to fight therefore, a 1:1 mating ratio is the most effective option. Female hamster usually reaches maturity at 5–6 weeks of age and is able to breed from 6–7 weeks of age. Male hamster reaches maturity at 6–8 weeks of age and is fertile from 12 weeks of age. Some studies have shown the effective use of ultrasound backscatter microscopy in examining the fetal development in mice, in particular the development of the embryonic eye, heart, and central nervous system. Ultrasound examination is used experimentally in some small laboratory animals, such as rabbits, rats, and agoutis. Pregnancy ultrasound examination is common in domestic animals (e.g., horse, cattle, goat, sheep, swine, dog, and cat), laboratory animals (e.g., ferret, guinea-pig, rabbit, and rat), exotic ungulates (e.g., deer, antelopes, anoa, banteng, giraffe, camelids, and rhinoceros), and zoo and wild animals (e.g., primates, dolphin, shark, and opossum). Hamster is also used in reproductive toxicology studies that require early detection of pregnancy and identification of fetal growth abnormalities. Hamster is a polytocous animal with a short length of pregnancy period and is widely used as an experimental model in the study of human reproduction system. Abdominal palpation, as a method of pregnancy diagnosis, can only be used from mid-to-late pregnancy in laboratory animals. Up until recently, the use of ultrasound has been restricted to non-rodent species. Ultrasound has been widely used to assess human pregnancy, but it has not been very common in studies of pregnancy in animals. Real-time ultrasound can be used for the diagnosis of pregnancy and estimation of fetal age in golden hamster from day 7 of gestation. Statistical analysis revealed that the ultrasound estimation of gestational age was significantly correlated with the actual age of the fetus (r = 0.98 p < 0.05). The gestational sac and crown-rump length were identified and measured by ultrasonographicly on day 7 of pregnancy and head could be visible after day 10 of gestation. On each day of the experiment, at least one of the pregnant hamsters was euthanized and dissected for macroscopic fetal measurements using a digital caliper. After seven days of mating, the hamsters were examined daily for pregnancy diagnosis and aging with an ultrasound scanner equipped with an 8.5-MHZ linear probe. During estrous (18 h after hCG injection), the hamsters were naturally mated. The estrous cycle was synchronized using eCG and hCG. Ten adult female golden hamsters were selected and maintained under controlled light conditions (14 h light/10 h darkness). Furthermore, a macroscopic examination was performed to evaluate the embryonic vesicle diameter, crown-rump length, and fetal head diameter. Current study describes use of trans-abdominal ultrasonography for pregnancy diagnosis and fetal age estimation in golden hamster. ultrasonography have been used in diagnosis of pregnancy in some small laboratory animals, such as rabbits, rats, and mice. However, pregnancy diagnosis and aging always have been a challenge. Hamster is widely used as an experimental model in the study of reproductive system.
0 Comments
Leave a Reply. |