Zinc di(acetate)

Repeated dose toxicity: other routes

Administrative data

Endpoint:

short-term repeated dose toxicity: other route

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2003

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: A scientifically defensible approach was used to conduct the study. In accordance with SOT Guiding Principles in the Use of Animals in Toxicology, 1989. No data on GLP.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Toxic effect of Zinc acetate on the functions of various tissues and organs in rats was studied.
The rats were randomly divided into groups (14 in each group). One normal control group received saline and two groups received zinc acetate (4 mg/kg bw/day and 8 mg/kg bw/day) and the other group cyclophosphamide (50 mg/kg bw, as a positive control of micronucleated polychromatic erythrocytes).
The saline and zinc acetate were administrated intraperitoneally to the rats once every two days, seven times in total. Cyclophosphamide was given intraperitoneally to the rats once.
The concentration of blood zinc was determinated.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Zinc di(acetate)

EC Number:

209-170-2

EC Name:

Zinc di(acetate)

Cas Number:

557-34-6

Molecular formula:

C2H4O2.1/2Zn

IUPAC Name:

zinc diacetate

Details on test material:

- Name of test material (as cited in study report): Zinc acetate
- Substance type: discrete
- Physical state: solid

Test animals

Species:

rat

Strain:

Wistar

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Animal center of the Chinese Medical University.
- Weight at study initiation: 160-190 g
- Fasting period before study: food allowed ad libitum
- Acclimation period: 1 week
- Water (e.g. ad libitum): yes

ENVIRONMENTAL CONDITIONS
- Temperature (°C): controlled
- Photoperiod (hrs dark / hrs light): 12 h dark-light cycle

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

not specified

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

14 days

Frequency of treatment:

The control group and the two zinc groups were treated once every two days, seven times in total. The positive control was only administered once.

Doses / concentrations

Remarks:

Doses / Concentrations:
4 mg/kg bw/day and 8 mg/kg bw/day of Zinc acetate.
50 mg/kg bw of cyclophosphamide as a positive control.

No. of animals per sex per dose:

Fourteen male rats/dose

Control animals:

yes

Details on study design:

- Dose selection rationale: based on publications data

Examinations

Observations and examinations performed and frequency:

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the study
- Anaesthetic used for blood collection: No data
- How many animals: 10
- Parameters checked: Zinc concentration.

CLINICAL CHEMISTRY: Yes
- How many animals: 10
- Parameters checked: effect of heme in rats, frequency of BSE (basophilic stippled erythrocyte).

Sacrifice and pathology:

GROSS PATHOLOGY: No
HISTOPATHOLOGY: No

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

not specified

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

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

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

not specified

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

not specified

Effect levels

1

Dose descriptor:

dose level:

Effect level:

4 other: mg/kg bw/48hx7 (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Concentration of blood Zn: 7.28 (± 1.62) μg/g

2

Dose descriptor:

dose level:

Effect level:

8 other: mg/kg bw/48hx7 (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Concentration of blood Zn: 7.31 (± 1.76) μg/g

3

Dose descriptor:

dose level:

Effect level:

4 other: mg/kg bw/48hx7 (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Concentration of blood δ-ALA: 83.68 (± 40.5) mol/L

4

Dose descriptor:

dose level:

Effect level:

8 other: mg/kg bw/48hx7 (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Concentration of blood δ-ALA: 112.5 ( ± 60.1) mol/L

5

Dose descriptor:

dose level:

Effect level:

4 other: mg/kg bw/48hx7 (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Frequency of Basophilic Stippled erythrocyte: 4.2 (± 1.3 %).

6

Dose descriptor:

dose level:

Effect level:

8 other: mg/kg bw/48hx7 (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Frequency of Basophilic Stippled erythrocyte: 4.5 (± 1.3 %).

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

Concentration of blood zinc in rats

The average concentration of blood zinc in 10 rats of each group after the seven treatments of salineor Zinc acetate is shown in in Table 1.

The concentration of blood zinc was 6.90 µg/g in the control group, and 7.28 and 7.31 ( µg/g, respectively, in the Zn_lowand Zn_highgroups. There were no significant differences in the concentration of blood zinc between the two groups that received zinc acetate or saline(P>0.05).

 

Table 1: Concentration of blood Zn in rats.

groups	Zinc acetate mg/kg	Number of rats	Concentration of blood Zn (mean ±S.D., µg/g)
Normal control	-	10	6.90 A 2.25
Znlow	4	10	7.28 ± 1.62
Znhigh	8	10	7.31 ± 1.76

 

Note: Zinc acetate was intraperitoneally administered to rats once every 2 days a total of seven times.

 

 

Effect of Zn on the concentration of blood δ-ALA in rats

 

The concentration of blood δ-ALA in 10 rats of each group after the seven treatments of saline or zinc acetate is shown in Table 2.

 

Table 2: Effect of zinc of heme in rats.

Groups	Zinc acetate (mg/kg)	No. of rats	Concentration of bloodδ-ALA (mean ± S.D., mol/L)
Normal control	_	10	87.4 ± 40,6
Znlow	4	10	83.6 ± 40.5
Znhigh	8	10	112.5 ± 61.1

 

 

Effect of Zn on frequency of BSE in rats

 

The frequency of BSE in the three groups of rats is shown in Table 3.

The frequency of BSE was 2.9, 4.2 and 4.5, respectively, in the control, Zn_lowand Zn_highgroups. There was a significant difference in the frequency of BSE between the Zn_highgroup and the control group (P< 0.05).

 

Table 3: Effect on the frequency of BSE in rats.

Groups	Zinc acetate (mg/kg)	No. of rats	Frequency of BSE (%) (mean ± S.D.)
Normal control	_	10	2.9 ± 2.3
Znlow	4	10	4.2 ± 1.3
Znhigh	8	10	4.5± 1.3*

BSE: basophilic stippled erythrocyte,

*P <0,05, compared with normal control group.

Effect of Zn on the micronucleus frequency in bono morrow cells of rats

 

The frequency of MPCE in the bone marrow of rats is shown in Table 4. The frequency of MPCE in the normal control group that received saline only and the positive control group that received cyclophosphamide alone was 3.3 and 18, respectively, The frequency of MPCE in the Zn_low group and the Zn_high, group was 3.5 and 6.3, respectively, and the latter increased significantly (P<0.05), compared with the former and the normal control group.

 

Table 4: Effect of Zn on the micronucleus frequency in bono morrow cells of rats.

Groups	Zinc acetate (mg/kg)	No of rats	No. of spermin	No. Of MPCEs	Frequency
Normal control	_	7	7000	23	3.3
Znlow	4	7	7000	25	3.5
Znhigh	8	7	7000	44	6.3^a,b
Positive control 50mg/kg cyclophosphamide	-		7000	126	18.0^c

 CP: cyclophosphamide, Positive control: group that received 50mg/kg cyclophosphamide only. PCEs: polychromatic erythrocytes; MPCEs: micronuclented polychromatic erythrocytes. The number of MPCEs in 1000 PCEs per animal was scored.

^aP <0.05, compared with normal control group.^bP < 0.05, compared with Zn_lowgroup.^cP<0.01, compared with normal control group.

Effect of Zn on the rale of abnormal sperm in rats

 

The rate of abnormal sperm in each group of rats is shown in Table 5. The rate of abnormal sperm was 7.7 in the normal control group. In the Zn_low group and Zn_highgroup, the rate of abnormal sperm was 6.0 and 8.0, respectively, and there were no significant differences compared with the normal control group.

 

Table 5: Effect of Zn on the rate of abnormal spermin in rats.

Groups	Zinc acetate (mg/kg)	No of rats	No. of spermin	No. of abnormal spermin	Rale of abnormal spermin (%)
Normnl control	_	7	7000	54	0.77
Znlow	4	7	7000	42	0.60
Znhigh	8	7	7000	56	0.80

 

No significant differences(P>0.05), compared with normal control group .

 

 

Effect of Zn on the levels of serum GPT, GOT, AID and LDH in rats

The levels of four kinds of serum enzymes in each group of rats are shown in Table 6. There were no significant differences between the two experimental groups and the normal control group(P>0.01),

 

Table 6.Effect of Z non the levels of serum GPT, GOT, AID and LDH in rats.

Groups	Zinc acetate (mg/kg)	No of rats	Levels of serum enzymes (mean ± S.D., nmol/mL)
			GPT	GOT	ALD	LDH
Normal control	-	10	3.68 ± 0.72	1,14± 0,15	4.52 ± 1.57	26.72 ± 5.82
Znlow	4	10	3.33± 0.55	1.13 ± 0,22	4.85± 1.09	25.82 ± 7.10
Znhigh	8	10	3.54± 0.78	0.88±0.22^a,b	4.68± 1.23	27.07 ± 0.85

   

^aP <0.01, compared with normal control group.^bP<0.05, compared with Zn_lowgroup

^bP <0.01, compared with normal control group.^bP<0.05, compared with Zn_lowgroup.

Effect of Zn on the level of serum thyroid hormone in rats

 

The level of serum T3 were significantly differences between each of the experimental groups and the normal control group (P<0.05).

The level of serum T4 and of serum TSH were no significantly differences between each of the experimental groups and the normal control group (P>0.05).

 

Table 7.Effect of Zn on the level of serum thyroid hormone in rats

Groups	Zinc acetate (mg/kg)	No of rats	Levels of hormones
			T3 (nmol/L)	T4  (nmol/L)	T5  (nmol/L)
Normal control	-	10	1.54 ± 0.59	29.7± 7.79	12.74 ± 6.91
Znlow	4	10	0.91± 0.40	25.± 6.22	12.93± 4.83
Znhigh	8	10	1.01± 0.30^a	29.70± 7.75	10.32± 4.16

^aP <0.05, compared with normal control group

 

 

Effect of Zn on the level of serum adrenal cortical hormone in rats

The level of serum Cortisol in each group of ratsisshown in Table 8. The level of serum Cortisol was 7.54 nmol/L in the normal control group, and 10.82 and 14.55 nmol/Linthe Zn_low and Zn_high, groups, respec­tively. In the Zn_highgroup, there was a significantly increase in the level of serum Cortisol, compared to the normal control group(P<0.01) and the Zn_lowgroup (P< 0.05).

Table 8. Effect of Zn on the level of serum adrenal cortical hormone in rats

Groups	Zinc acetate	No of rats	Level of serum cortisol (nmol/L)
Normal control	-	10	7.54 ± 3.7
Znlow	4	10	10.82 ± 4,9
Znhigh	8	10	14.55 ±2,7 *

* P <0.01, compared with normal control group, P <0.05, compared with Zn_lowgroup.

 

 

Applicant's summary and conclusion

Conclusions:

The dose of 8 mg/kg bw of zinc acetate increased the frequencies of basophilic stippled erythrocyte (BSE), concentration of bloodδ-ALA and the frequencies of MPCEs (micronucleated polychromatic erythrocytes).
The levels of serum glutamic oxalacetic transaminase (GOT) and serum triiodothyronine (T3) in this group decreased significantly, compared with the control group. Moreover, it was observed that the level of serum cortisol was increased.
Also was observed that zinc acetate at the same dose did not cause and elevated abnormal sperm percentage in rats indicating that zinc does not have a harmful effect on the male reproductive system.

Executive summary:

The aim of the assay was to observe the toxic effects of the zinc on the functions of various tissues and organs of rats.

The dose of 8 mg/kg bw of zinc acetate increased the frequencies of basophilic stippled erythrocyte (BSE), concentration of bloodδ-ALA and the frequencies of MPCEs (micronucleated polychromatic erythrocytes).

The levels of serum glutamic oxalacetic transaminase (GOT) and serum triiodothyronine (T3) in this group decreased significantly, compared with the control group. Moreover, it was observed that the level of serum cortisol was increased.

Also was observed that zinc acetate at the same dose did not cause and elevated abnormal sperm percentage in rats indicating that zinc does not have a harmful effect on the male reproductive system.