Postimplantation whole embryo culture assay for hamsters: an alternative to rat and mouse.

Postimplantation whole embryo culture (WEC) assay for rats and mice has been well established and introduced to many laboratories. Recently WEC technique for rabbits has been developed; however, information on culture of other species is very limited. Knowing the usefulness of hamsters in classical embryotoxicology, we reasoned that hamster WEC could be an alternative model for the most frequently used rat and mouse WEC. Previously we have optimized culture conditions for postimplantation hamster embryos. The aim of this study was to test the susceptibility of hamster embryos cultured in vitro to embryotoxic compounds and to compare our results with those reported by others on rat or mouse embryo culture. For that purpose we choose three known embryotoxic compounds--valproic acid, cadmium chloride, and diethylstilbestrol--and tested them using a postimplantation hamster whole embryo culture assay. Hamster embryos were cultured from 7.5 days gestation for 24 h in a medium consisting of 35% hamster serum and 65% synthetic culture medium (Iscove's or McCoy 5A). At the end of the culture period, the embryos were examined morphologically, measured with the aid of a computer image analysis system, and total protein content was assessed. All three compounds exhibited dose-related embryotoxic and teratogenic effects in hamster embryos. The malformations observed were similar to those reported on rat and mouse embryos. Comparison of the results with data reported by other authors indicates that hamster embryos cultured in vitro might be more susceptible to embryotoxic stimuli than rat and mouse embryos.

[Teratogenic action of antiepileptic drug: 2-propylpentanoic acid-effects on rat and hamster embryos cultured in vitro]. / Teratogenne dzialanie leków przeciwpadaczkowych na przykladzie kwasu 2-propylowalerianowego: wplyw na zarodki szczura i chomika hodowane in vitro.

Valproic acid (2-propylpentanoic acid) has become accepted as one of the most important antiepileptic drug. Although clinically effective, this drug remains controversial as suspected of being a human teratogen. The aim of our study was to test the embryotoxic potential of valproic acid using whole embryo culture assay. For that purpose rat and hamster embryos were explanted on gestation day 9 and 7 respectively, and cultured for 48 and 24 hours. During the culture period embryos were exposed to valproic acid (VPA) at a concentrations of: 10, 50 and 100 mg/ml. In our study this drug exhibited dose-related embryotoxic and teratogenic effects in rat and hamster embryos. Analysis of the results indicated that hamster embryos were more susceptible to VPA than rat embryos.

[Micrometric and morphological assessment of early stage rat embryos -- application for in vivo teratology testing]. / Mikrometryczna i morfologiczna ocena wczesnego stadium rozwojowego zarodków szczura--zastosowanie w doswiadczalnej teratologii in vitro.

Authors presented the whole embryo culture (WEC) method suggested for embryotoxicity study. The present paper concentrates on morphological scoring system proposed by Brown and Fabro in 1981. The scoring system provides a precise index of embryonic development and allows a quantitative comparison of development and growth. In our study we used this system with slight modification for assessing an 86 control rat embryos. We have found that routine use of this scoring system in teratology embryo culture experiments may afford further benefits.

Studies on the embryotoxic and teratogenic effects of Tolpa Peat Preparation.

Neither embryotoxic nor teratogenic effects were observed in hamsters and rats after administration of Tolpa Peat Preparation (TPP) in doses of 5 and 50 mg/kg daily. Some maternal toxicity in rats and some embryotoxic effect in hamsters were recorded after the highest dose of TPP (250 mg/kg daily).

Teratological evaluation of Ukrain in hamsters and rats.

The compound Ukrain, containing thiophosphoric acid alkaloid derivatives from the plant Chelidonium majus L., was given intramusculary (i.m.) on days 6-11 of gestation to hamsters and on days 6-15 of gestation to rats in doses of 0.1, 1.67 and 28 mg/kg daily. No clinical signs of toxicity were found in treated animals and no teratogenic effect could be noted in either species. Such parameters as the number of corpora lutea, implantation sites, pre and post-implantation losses, number of live foetuses per litter, placental weight, foetal weight and crown-rump length were not significantly different between the Ukrain treated rats and the controls. Slight embryotoxic effects (increased post-implantation losses) and in consequence decreased number of average litter size were noted in hamsters exposed to Ukrain at doses which were otherwise not embryotoxic to rats.

[Usefulness of male golden hamsters for experimental reproductive pathology]. / Przydatnosc samców chomika zlocistego do badan w zakresie patologii rozrodu.

Seventy two male Golden hamsters were maintained in normal laboratory conditions (12h light-dark cycle, 20 +/- 2 degrees C) for the annual cycle experiment. Every month 6 animals were sacrificed and testis weight, cauda epididymis weight, caudal sperm number, sperm morphology and body weight were determined. The period of high gonadal activity was found to be from March to the end of July. In September reproductive activity decreased and the low activity period, with azoospermia in some animals, lasted till the end of January. This annual reproductive cycle, shown for the male Golden hamsters, should be taken into consideration when designing new experiments and interpreting their results.