Ditin pyrophosphate

Toxicity to reproduction

Administrative data

Endpoint:

one-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study conducted under GLP conditions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Tin(II) bis(methanesulfonate)

EC Number:

401-640-7

EC Name:

Tin(II) bis(methanesulfonate)

Cas Number:

53408-94-9

Molecular formula:

Sn(CH_{3} SO_{3} )_{2}

IUPAC Name:

bis(methanesulfonyloxy)stannanylidene

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Charles River Deutschland, Germany
- Age at study initiation: (P) x 6 wks; (F1) x wks
- Fasting period before study:none
- Housing:individually in polycarbonate (Makrolon®) cages type III
- Diet : ad libitum
- Water: ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C):20 – 24
- Humidity (%):40 - 70
- Photoperiod (hrs dark / hrs light):12/12

Administration / exposure

Route of administration:

oral: feed

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet : once prior to study initiation, second as needed
- Mixing appropriate amounts with :V1324, purchased from ssniff Spezialdiaeten GmbH, Soest, Germany
- Storage temperature of food:not reported

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: 2 weeks
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged :individually

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

After the sample (5 pellets) was powdered and homogenized, approx. 100 mg (exactly weighed) were suspended in 0.5 ml CD3CN/D2O (50/50 v/v). After addition of 10 μl of an aqueous solution of maleic acid (c=100 mg/ml) as internal standard the tin methylsulfonate was extracted ultrasonically. Quantification of the test item was then carried out by 1H NMR spectroscopy.

Food was analyzed immediately after receipt, 5 weeks and 10 weeks after delivery.

Duration of treatment / exposure:

The animals were treated via food for 10 weeks before mating and during the mating period. After successful mating (day of finding sperm in vaginal smears = day 0 post conceptionem [p.c.]), treatment of the females was continued until weaning of the offspring and subsequent sacrifice. Exposure of all males and females continued until their sacrifice after determination of sexual maturation in offspring. Animals selected for the investigation of sexual maturation were exposed from weaning to sacrifice.

Frequency of treatment:

7 days/week

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 1200, 3500, and 7000 ppm
Basis:
nominal in diet

No. of animals per sex per dose:

24

Control animals:

yes, plain diet

Details on study design:

- Dose selection rationale: High dose chosen based on 90 day toxicity study (oral gavage) and range fining study showing marked reduction in body weight at the high dose level, other doses used a stagger of approximately 2-3.
- Rationale for animal assignment:random

Examinations

Parental animals: Observations and examinations:

CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly (males, females prior to mating), after mating females weighed 0, 4, 7, 10, 14, and
20 post conception and days 0, 4, 7, 14, and 21 post partum

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

Oestrous cyclicity (parental animals):

yes

Sperm parameters (parental animals):

Parameters examined in [all/P/F1/F2] male parental generations:
[testis weight, epididymis weight, daily sperm production, sperm count in testes, sperm count in epididymides, enumeration of cauda epididymal sperm reserve,]

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in [F1] offspring:
[number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities, sexual maturation]

GROSS EXAMINATION OF DEAD PUPS: no

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals as soon as possible after the last litters in each generation were weaned and evaluated.
- Maternal animals: All surviving animals after the last litter of each generation was weaned and evaluated.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
none

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring were sacrificed at 21 days of age except those evaluted for sexual maturation
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows:Necropsy was performed in all animals selected for investigations of sexual maturation. The following organs and tissues were collected from each rat and fixed in 10% neutral buffered formalin: Brain, pituitary, tongue, eyes, lacrimal glands, nasal and paranasal cavities, larynx, pharynx, trachea, thyroid, parathyroids, lungs, thymus, heart, aorta, lung-associated lymph nodes, salivary glands, mandibular lymph nodes, liver, pancreas, spleen, kidneys, adrenals, oesophagus, forestomach, glandular stomach, duodenum, jejunum, ileum, caecum, colon, rectum, mesenterium and lymph nodes, urinary bladder, testes (fixation in modified Davidson‘s fluid), epididymides (fixation in modified Davidson‘s fluid), prostate incl. coagulating glands, seminal vesicles, ovaries with oviduct (fixation in modified Davidson‘s fluid), uterus, vagina, mammary glands, skeletal muscle, femur including joint, vertebrae with spinal cord, skin, peripheral nerve, sternum with bone marrow.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGTHS
The organ weights of uterus, ovaries, testes, epididymides, seminal vesicles, and prostate.
The following organs and tissues from each rat of the high-dose and control group were investigated histopathologically: vagina, uterus, oviducts, cervix, ovaries, testes, epididymides, seminal vesicles, prostate, and coagulating glands.

Statistics:

Statistical comparison of groups was performed separately for each sex at the level of =0.05. Parental and offspring weights as well as food consumption were analyzed using analysis of variance. If the group means differed significantly with this method, the means of the treatment groups were compared with the mean of the control group 1 using Dunnett's modification of the t-test. Kruskall-Wallis ANOVA and Mann-Whitney U-test were applied in the case of non-normal data. Qualitative reproduction data were analyzed using the two-tailed FISHER test with Bonferroni correction or Chi-square test. In the results the p-value indicates the minimum for which the Bonferroni-corrected test was significant. Histopathology data were analyzed using the two-tailed FISHER test.
In all instances, the dam or litter was used as the basic unit. Postmating data and organ
weights of females without implantation sites were excluded from statistical analysis.

Reproductive indices:

Female fertility index, male fertility index, female mating index, male mating index, gestation index

Offspring viability indices:

livebirth index, viability index, lactation index

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings: non-neoplastic:

not examined

Other effects:

no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)In males, the differences from the control group reached statistical significance in the high and medium dose group between day 0 and 7. The same was observed for high dose females only. These effects are in good concordance with the influences observed on body weight gain. All values returned to normal. No effects were observed during gestation or lacation.No effect was observed on the number of implantation sites, pup birth weight, number of live pups or pup loss during lactation, duration of gestation and sex ratio of pups.

Effect levels (P0)

Dose descriptor:

NOAEC

Effect level:

ca. 100 mg/kg bw (total dose)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: body weight and body weight gain at the start of treatment of the parental generation were decreased in males of the high and medium dose as well as females of the high dose group

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings:

effects observed, treatment-related

Details on results (F1)

VIABILITY (OFFSPRING): Similar between control and treated animals

CLINICAL SIGNS (OFFSPRING): Similar between control and treated animals

BODY WEIGHT (OFFSPRING) decrease in pup weight in the second half of lactation, which reached statistical significance in the high dose group on day 21 (when pups began to eat ); trend for decreased body weight in males

SEXUAL MATURATION (OFFSPRING): Similar between control and treated animals

ORGAN WEIGHTS (OFFSPRING): No effect relative organ weights, In the high dose group decreased weight of testes, epididymides, and ovaries were noted

GROSS PATHOLOGY (OFFSPRING): No significant differences

HISTOPATHOLOGY (OFFSPRING) Testes - Slight (multi)focal tubular atrophy was seen in one out of 23 males of the control and 2/21 males of the high dose group. Very slight/slight and moderate degeneration of round spermatids and/or pachytene spermatocytes was detected in four males of the high dose group and associated with slight depletion of round and elongated spermatids in one of these males. Degeneration of spermatids was also observed in 1/23 control males at a very slight severity.
Epididymides - Moderate hypospermia and exfoliation of germ cells into the efferent ducts was found in two males of the high dose group (2/21). Two males (2/21) of the high dose group showed only very slight exfoliation of germ cells into the epididymides.(Multi)focal very slight interstitial mononuclear cell infiltration was seen in 6/23 males of the control group and in 7/21 males of the high dose group. One male (1/23) of the control group
revealed a small granuloma.
Prostate - Very slight interstitial/intra-acinar inflammatory cell infiltration was observed in 4/23 males of the control and in 1/21 males of the high dose group.
Uterus - Very slight or slight dilated uterine horns were observed in 5/23 females of the control group and in 7/21 females of the high dose group. These dilatations are due to accumulation of fluid dependent on hormonal influences during the estrous cycle.

OTHER FINDINGS (OFFSPRING) No effect was observed on the number of implantation sites, pup birth weight, number of live
pups or pup loss during lactation, duration of gestation and sex ratio of pups. No effect was observed on the time of showing preputial separation or vaginal opening in any of the test item treated groups

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

ca. 300 mg/kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

other: see 'Remark'

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

It cannot be excluded that the statistically significantly slightly increased incidence of exfoliated germ cells in the lumina of the efferent ducts of the epididymis in the high dose group is due to degenerative lesions in the testes induced by the test item. The findings in the epididymis correspond with very slight, slight and in one male of the high dose group even with moderate testicular changes. Even if the observed degenerative lesions in the testes are not statistically significant compared to the control, they show a tendency to occur more frequent and in a slightly higher severity in the high dose group. The background level of sloughed cells in the epididymis is very low in adult control rats but might be increased in young respectively peripubertal rats so it might reflect age rather than toxicity. As the age range over which rats mature extends from 8-10 weeks so it can happen "by chance" that a higher incidence of rats with incomplete spermatogenesis, increased germ cell degeneration and sloughed germ cells in the epididymidal lumen will be present in the high dose group and the more normal mature testes will be in the control group. In this situation it is difficult to distinguish whether the increased germ cell degeneration, the presence of sloughed germ cells in the epididymal lumen and the reduced epididymal sperm in the high dose group is due to a degenerative lesion induced by the test compound or a reflection of relative immaturity. All these gonadal effects could also be explained by the fact that body weight in the high dose animals was decreased compared to the control group, thus reflecting developmental retardation.

Applicant's summary and conclusion

Conclusions:

The no observed adverse effect level of Tin(II)methane-sulfonate in this One-generation reproduction toxicity study in Wistar WU rats was determined
at a concentration of 3500 mg/kg food (target dose of 300 mg/kg body weight/day) for developmental endpoints, and 1200 mg/kg food (target dose of 100 mg/kg body weight/day) for adult endpoints. These values are based on the finding that body weight and body weight gain at the start of treatment of the parental generation were decreased in males of the high and medium dose as well as females of the high dose group. This effect was also replicated in selected postweaning offspring high dose males and high and medium dose females. In preweaning offspring, the only effect observed was a decrease of pup weight in the second half of lactation, which reached statistical significance in the high dose only group on day 21. This effect occurred only when pups began to eat food in addition to maternal lactation and, therefore, can be interpreted as a repellent effect of the food containing higher doses of the test item, which was also observed in the beginning of treatment in F0 animals and not as a specific reproductive or developmental effect and can also be the reason for the observed slight effects on offspring gonads