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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
2009
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline study but otherwise adequate for assessment.

Data source

Reference
Reference Type:
publication
Title:
Semen parameters, fertility and testosterone levels in male rats exposed prenatally to betamethasone
Author:
Piffer, R.C.; Garcia, P.C.; Gerardin, D.C.; Kempinas, W.G.; Pereira, O.C.
Year:
2009
Bibliographic source:
Reprod. Fertil. Dev. 2009, 21, 634-639.

Materials and methods

Principles of method if other than guideline:
Betamethasone 21-phosphate was injected to pregnant rats on day 12, 13, 28, and 19. the betamethasone treatment corresponds to theraphy used in pregnant woman. Days 12 and 13 were selected as during organogenesis of fetuses. Days 18 and 19 coincide with the time of greater vulnerability because of testosterone peak of producion.
Sperm quality and count of the offspring in their adulthood (Postnatal Day 90) were examined. At the same time plasma concentration of testosterone and fertility were evaluated.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Betamethasone 21-phosphate disodium

Test animals

Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Multidisciplinary Center for Biological Investigation, State University of Campinas, Brazil
- Age at study initiation: 90 days old
- Weight at study initiation: 230 ± 10 g

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 25 ± 1°C
- Humidity (%): 55 ± 5%
- Photoperiod (hrs dark / hrs light): light fropm 06.00 to 18.00

Administration / exposure

Route of administration:
intramuscular
Vehicle:
physiological saline
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused: mated with one fertile untreated male of the same age
- M/F ratio per cage: 1/1
- Length of cohabitation: till the morning on which spermatozoa were found in the smear
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: sperm in vaginal smear referred to as day 1 of pregnancy
Duration of treatment / exposure:
Betamethasone was injected in four days of pregnancy: day 12, 13, 18, and 19
Frequency of treatment:
Daily
Duration of test:
The offspring was analyzed till day 90 of life (adulthood)
Doses / concentrations
Remarks:
Doses / Concentrations:
0.1 mg/kg betamethasone diluted in sterile physiological solution
Basis:
nominal conc.
No. of animals per sex per dose:
8 female rats
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The betamethasone treatment corresponds to therapy used in pregnant woman, and the treatment period was selected based on the corticosteroid therapy administered to women at risk of premature delivery. Thus, was started at the end of the first half of pregnancy and the second course of treatment, on day 18 and 19, was administered during the period of brain sexual differentiation.
- Rationale for animal assignment (if not random): random assigned

Examinations

Statistics:
Student's t-test, the Mann-Whitney U-test and Fisher's exact test were used, with results considered significant at P<0.05.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:no effects

Effect levels (maternal animals)

Dose descriptor:
dose level:
Effect level:
0.1 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Prenatal treatment with betamethasone may result in decreased endogenous levels of testosteronein male pups, which are crucial for brain sexual differentiation, with conseguent drop of testosterone production in adulthood, in association with damaged semen parameters.

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Only relevant data is reported.

   Control  Betamethasone-treated
 Sperm concentration (x 106)  77.8 ± 5.6  57.0 ± 4.4 (p<0.01 Student's t-test)
 Motility (%)  67 (59 -75)  61 (38 -64) (p<0.05)
 No. spermatidis (x106 per testis)  241 ± 6  197 ± 4 (p<0.001 Student's t-test)
 Testosterone level (ng dL-1)  393 ±53  187 ± 19 (p<0.05 t-test with Welch correction)
 Testis weight (g)  1.60 ± 0.03  1.48 ± 0.04 (p<0.05 Student's t-test)

Rates of implantation, pre- and post-implantation losses and fetal viability in pregnant female rats mated with male control rats and males exposed prenatally to betamethasone

   Control (n=10)  Betamethasone-treated (n=8)
 Implantation (%)  100 (93 -100)  87 (61 -89) (p<0.05 Mann-Whitney U-test)
 Post-implantation loss (%)  8 (8 -11)  31 (25 -43) (p<0.05 Mann-Whitney U-test)
 Fetal viability (%)  100 (97 -100)  75 (61 -89) (p<0.05 Mann-Whitney U-test)

Applicant's summary and conclusion

Conclusions:
Prenatal treatment with betamethasone led to significant reduction in sperm concentration and spermatid number.
In adult male rats, prenatal exposure to betamethasone led to a significant reduction in plasma testosterone concentration. Derease of testosterone production led to long term effects on fertility of adult male rats.