Phthalates are chemicals interfering with the function of testosterone and are suspected to play a role in the emergence of neurodevelopmental diseases. This could be due to interference with brain development for which optimal testosterone levels are essential. We investigated the effect of prenatal and early postnatal exposure to a phthalate mixture on the anogenital distance (AGD), plasma testosterone levels and social behavior in rats. Pregnant rats were exposed to a mixture of diethylhexyl, diisononyl and dibutyl phthalate, each at a dose of 4.5 mg/kg/day, from gestational day 15 to postnatal day 4. A social interaction test was performed to assess sociability in the three ontogenetic stages (weaning, puberty, adulthood). AGD was measured in adulthood to assess changes in prenatal testosterone levels. Plasma testosterone levels were measured in adults by a radioimmunoassay. The total frequency and time of socio-cohesive interactions were decreased in phthalate exposed females in weaning, puberty and adulthood. Phthalate exposed males showed a decrease in the frequency of social interactions in weaning only. Shorter anogenital distance was observed in adult males exposed to phthalates. Decreased testosterone levels were observed in the exposed group in both sexes. Our results suggest that early developmental phthalate exposure may play an important role in the hormonal and behavioral changes associated with several neurodevelopmental diseases.
Fascioliasis due to Fasciola hepatica (Linnaeus, 1758) is an endemic disease on the Northern Bolivian Altipiano, where human prevalences and intensities arc the highest known, sheep and cattle are the main reservoir hosts, and pigs and donkeys the secondary ones. Investigations were carried out to study the viability of metacercariae experimentally obtained from eggs shed by naturally infected Altiplanic sheep, cattle, pigs and donkeys. A total of 157 Wistar rats were infected with doses of 5, 10, 20 and 150 metacercariae. Metacercariae aged for different number of weeks were used to analyse the influence of age on their viability. The number of worms successfully developed in each rat was established by dissection. Results obtained show that metacercarial infectivity is dependent upon storage time, being lower when metacercariae arc older. The maximum longevity is 31 weeks using doses of 20 metacercariae per rat and 48 weeks with 150 metacercariae per rat, although in the latter case only a very low percentage of worms is recovered. Age-related infectivity of metacercariae from Altiplanic F. hepatica does not significantly differ from that of the liver fluke in lowlands of other countries. Concerning the influence of the isolate according to host species, results indicate that metacercarial viabilities of pig and donkey isolates are similar to the viabilities of metacercariae of sheep and cattle isolates. Thus, pig and donkey have a high transmission potential capacity concerning this aspect. This fact is of great importance for the control of human and animal fascioliasis in this highly endemic zone.
The purpose of the study was to test the hypothesis of different distribution spaces of elements in the rat mandibular bone and teeth. We used six adult males of Wistar laboratory rats for the study. After killing the animals, we extracted the molars and removed incisor crowns. The mandibular bone was divided into four parts (mesial-central-distal-ridge). Inductively coupled plasma mass spectrometry was used to determine the presence of 41 elements in the bone and tooth. Evidence of 14 elements was found in all samples (incisors-molars-bone). Generally, significant differences between the left and right side were found for K and Rb in the bone locations. As regards statistically significant differences in incisors-molars-bone locations, the elements for which these differences were found for all comparisons are listed as incisors versus individual molars, incisors versus bone locations, and individual molars versus bone locations: a) incisors-molars: Ba, Mn, Mo, Sr, Zn, K, Mg and Rb; b) incisors-bone: Fe, K, Mg, Mn, Na, Zn and Ba; c) molars-bone: Mn, Mo, Na and Mg. Statistically significant differences were also found between molars for Fe, Mg, Mn, and Sr and between bone locations for Ba, Ca, Mn, Sr, K, Rb, Zn, Mo, Mg, and Na. The elements Cu, Ni and Co were without pronounced differences. Twenty-seven elements were below the detection limit. Our results indicate different distributions of some elements in the rat mandibular incisors-molars-bone. We assume that the knowledge of chemical element contents in the laboratory rat bone and teeth will prove useful in experimental research of both these hard tissues. and Corresponding author: Ivo Němec