D-mannose

Endpoint summary

Description of key information

5 -Month drinking water study; mouse; NOAEL for systemic toxicity = 20% (highest dose tested); Reliability = 2

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

The study was conducted for 5 months

GLP compliance:

no

Limit test:

no

Species:

mouse

Strain:

other: C57 Bl/6

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: not reported
- Housing: individual cages
- Diet: standard rat chow ad libitum
- Water: dosed with test item ad libitum



ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 1 ºC
- Humidity (%): 55 ± 5%
- Photoperiod (hrs dark / hrs light): 12/12 hours

Route of administration:

oral: drinking water

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF TEST SUBSTANCE FORMULATION:

- Preparation frequency: drinking water was changed thrice a week

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

5 months

Frequency of treatment:

continuous

Dose / conc.:

1 other: %

Remarks:

nominal in water

Dose / conc.:

3 other: %

Remarks:

nominal in water

Dose / conc.:

10 other: %

Remarks:

nominal in water

Dose / conc.:

20 other: %

Remarks:

nominal in water

No. of animals per sex per dose:

3 male, 3 female per dose group

Control animals:

yes, concurrent no treatment

Details on study design:

During the 5 month treatment, females were impregnated twice. The pups were weaned at 21 days and maintained on the same test item dose as their mother for 9 days. Both mother and pups were monitored for ill health such as bloating, diarrhea and abnormal weight gain or loss. Behavior of these animals were also monitored.

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at 3 months
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: all

CLINICAL CHEMISTRY: Yes
- Animals fasted: No data
- How many animals: all

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: Yes
- Dose groups that were examined: all
- Battery of functions tested: mode of drinking and eating, climbing on the bars, grooming, social behaviour, and locomotion

OTHER: For reproduction data see Sec. 7.8.1: DL.K2.5Mon.DW.1Gen.M.Pub.KD

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, organs were examined for size and weight

HISTOPATHOLOGY: Yes

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Description (incidence and severity):

reduced consumption at 20%

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

increased compound levels in blood

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

GPT increased slightly

Urinalysis findings:

not specified

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Details on results:

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study):
- Water consumption in various groups was similar (4.5-6.0 mL/day), except for mice placed on 20% test item, where consumption was about half (2-2.5 mL/day) that of all others. Nevertheless, their average daily test item intake was still the highest. This reduction is presumably due to the bitter taste of the β-anomer of the test item.

HAEMATOLOGY:
- Oral test item intake lead to a dose-dependent increase in test item levels in the blood of males, females, and recently weaned pups. The test item also increased the level in the milk from nursing dams.

CLINICAL CHEMISTRY:
- Liver enzymes in plasma such as GOT and GPT were normal in both control and test item-fed mice (normal range: GOT, 40-50 IU/L; GPT, 15-25 IU/L)
except 10% test item-fed mice where GPT increased slightly, but was still within the normal range. Thus, there was no evidence of liver abnormalities.

OTHER FINDINGS:
- During 5 months of test item supplements, female mice were impregnated twice. Litter sizes (7-9 pups) and all pups were normal at birth. The dams continued on test item-supplemented water during nursing. Pups grew at a normal rate, were healthy, and all survived until weaning at 21 days. After that, the pups were placed on test item supplements for 9 days along with the mother.

Key result

Dose descriptor:

NOAEL

Effect level:

20 other: % in drinking water

Based on:

test mat.

Sex:

male/female

Basis for effect level:

water consumption and compound intake

Remarks on result:

other: % in drinking water

Critical effects observed:

not specified

To assess protein glycation, hemoglobin A1C (HbA1C) was measured in mice after 3 months. All groups showed nearly the same levels (2.9-3.1%) regardless of test item supplements, suggesting that glycated proteins do not accumulate in the blood in this animal.

All organ weights and their histological appearance were normal in all groups.

Conclusions:

This study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability).
Test item did not show any adverse or pathological effects on growth, behaviour, organ size or weight, accumulation of glycated hemoglobin, liver glycogen, serum transaminases or the histological appearance of any major organs or tissues.

Executive summary:

Test item-supplemented water given to mice for 5 months did not show any adverse or pathological effects on growth, behaviour, organ size or weight, accumulation of glycated hemoglobin, liver glycogen, serum transaminases or the histological appearance of any major organs or tissues. Those receiving 20% test item drank only half as much water as the control or the other groups. Nevertheless, their average daily test item intake was still the highest. Oral test item intake lead to a dose-dependent increase in test item levels in the blood of males, females, and recently weaned pups. The test item also increased the level in the milk from nursing dams. No adverse effects were seen on reproduction.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Study duration:

subchronic

Species:

mouse

Quality of whole database:

Comparable to guidleline study with acceptable restrictions

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The test item was administered in the drinking water at dose levels of 1%, 3%, 10% and 20% to mice for 5 months. During the 5 month treatment, females were impregnated twice. The pups were weaned at 21 days and maintained on the same test item dose as their mother for 9 days. Both mother and pups were monitored for ill health such as bloating, diarrhea and abnormal weight gain or loss. Behavior of these animals were also monitored. Test item-supplemented water given to mice for 5 months did not show any adverse or pathological effects on growth, behaviour, organ size or weight, accumulation of glycated hemoglobin, liver glycogen, serum transaminases or the histological appearance of any major organs or tissues. Those receiving 20% test item drank only half as much water as the control or the other groups. Nevertheless, their average daily test item intake was still the highest. Oral test item intake lead to a dose-dependent increase in test item levels in the blood of males and females.

Justification for classification or non-classification

Based on no adverse test substance-related effects at 20% (highest dose tested) in a 5-month mouse drinking water study, the test substance does not need to be classified for repeat dose toxicity according to EU Classification and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.