Brominated chlorinated copper, [29H,31H-phthalocyaninato(2-)-N29,N30,N31,N32]-, wherein the number of bromines is equal to or more than 10 and less than 16, and the number of chlorines is equal to or more than 0 and less than 7

Specific investigations: other studies

Administrative data

Endpoint:

biochemical or cellular interactions

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Principles of method if other than guideline:

The test material was incubated with Rat NR8383 alveolar macrophages in protein-free culture medium. Lactate dehydrogenase, glucuronidase, and tumour necrosis factor alpha were assessed after 16 h.

GLP compliance:

no

Type of method:

in vitro

Endpoint addressed:

repeated dose toxicity: inhalation

Test material

Test material information

Constituent 1

Test material form:

solid: nanoform, no surface treatment

Details on test material:

Surface area of particles: 35.9 m2/g (BET)
solid green
storage at room temperature
Expiry date: July 2026
Batch 16K1336
Name: Monastral Green 6Y-C

Specific details on test material used for the study:

Pigment Green 36
Purity ca 100%

Particles were dispersed according to the NanoGenotox protocol which uses small amounts of serum albumin to stabilize non-polar particles: A total of 15.36 mg of the dry powder was weighed into 20 mL glass vials, wetted with 30 μL ethanol, then mixed with 6 mL double distilled water containing 0.05% bovine serum albumin. The stock suspension contained 2.56 mg particles/mL, 0.5% (vol/vol) ethanol, and 0.05% bovine serum albumin. The stock suspension was ultrasonicated for 16 min with a Branson 450D sonifier. For experiments the stock suspension was mixed with one volume of double concentrated KRPG buffer or double concentrated F12-K medium, to achieve a physiological medium composition needed for the testing of cytotoxicity and cellular H2O2 generation, respectively. The resulting suspension was serially diluted in serum-free F12-K medium to obtain concentrations of 180, 90, 45 and 22.5 μg/mL. The suspension was also serially diluted in KRPG buffer, first to obtain 360, 180, 90, and 45 μg/mL; 100 μL of these suspensions were then added to cells covered with 100 μL of KRPG, to achieve the final test concentrations of 180, 90, 45 and 22.5 μg/mL.
Overall, this procedure resulted in a suspension which was sufficiently stable for in vitro testing. Nevertheless a partial sedimentation of components occurred such that all suspensions were vortexed prior to use.

Test animals

Species:

other: NR8383 cells (alveolar macrophage cell line derived from rat lung lavage cells)

Details on test animals or test system and environmental conditions:

For all experiments the alveolar macrophage cell line NR8383 (ATCC) was used and cultured according to ATCC guidelines in Ham's F-12K (Kaighn's) supplemented with L-glutamine, penicillin/streptomycin (PAA, Cat No: P11-010) and 15% FCS. Reduced concentrations of FCS (5%) were used prior to the assay for 24 h. Composition of KRPG-buffer was (in mM): NaCl (129 mM), KCl (4.86 mM), CaCl2 (1.22 mM), NaH2PO4 (15.8 mM), glucose (5.5 mM), pH 7.3-7.4.

Administration / exposure

Route of administration:

other: in cell culture

Vehicle:

other: F-12K medium and KRPG buffer (depending on the respective investigation)

Details on exposure:

The cell culture assays were carried out in 96 well plates using 4 concentrations of particles (in triplicates) which were pipetted onto NR8383 cells (3x105 cell/well) under serum-free conditions. After 16 h, supernatants were tested for LDH, glucuronidase (GLU) and TNFα-activity (in triplicates). Controls included untreated cells, Triton X-100-treated cells to fully release LDH and glucuronidase, and lipopolysaccharide (LPS)-treated cells to test for the macrophages' TNF production competence. Particle-free controls were run in duplicates for each particle concentration.
LDH activity was tested with Roche Cytotoxicity Detection Kit. The obtained values were background corrected and expressed as percentages of the Triton X-100-treated control. The untreated cell control amounted to <25 %, which is a typical base-line release of LDH from NR8383 cells under these conditions and does not indicate cell damage.
GLU activity was measured using p-nitrophenyl-β-D-glucuronide as a chromogen. The obtained values were background corrected and expressed as percentages of the Triton X-100-treated control. The cell controls amounted to < 3%, which is a typical base-line release of GLU from NR8383 cells and does not indicate cell damage.
Hydrogen peroxide concentration was measured cumulatively for 90 min post particle application. A parallel approach was carried out in KRPG buffer using the Amplex Red reagent. This assay is internally controlled using a standard concentration of 30 μM H2O2. Further, the cells' competence to produce H2O2 upon addition of zymosan was tested and found to be within the range of historical records.
Rat tumor necrosis factor α was quantified using a specific ELISA provided by bio-techne (Wiesbaden, Germany) according to the manufacturer’s protocol.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The particle suspension as prepared with the NanoGenoTox protocol was further diluted to measurable concentrations in dH2O, KRPG buffer or F-12K medium (to simulate the conditions of the cell culture) and analyzed by particle tracking analysis, which was carried out with a NanoSight instrument (LM10) equipped with a blue laser (405 nm) and NTA software (Version 3.1).

Duration of treatment / exposure:

16 h (for the determination of LDH, GLU, and TNF-α release)

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

22.5 other: μg/mL

Doses / concentrations 2

Dose / conc.:

45 other: μg/mL

Doses / concentrations 3

Dose / conc.:

90 other: μg/mL

Doses / concentrations 4

Dose / conc.:

180 other: μg/mL

Details on study design:

- Rat NR8383 cells, routinely cultured in F-12K medium supplemented with 2 mM glutamine, penicillin/streptomycin (100 U/10 mg/mL) and 15 % (v/v) fetal calf serum in 500 mL flasks under standard cell culture conditions (37 °C; 5 % CO2) and passaged once a week, were detached from the substrate by mechanical agitation, dispersed by pipetting, seeded into 96-well plates at 3 × 10^5 live cells per well and incubated in F-12K medium supplemented with 5 % FCS for 24 h. For test material application, supernatants were withdrawn, and test material-containing phenol red-free F-12K medium, supplemented with 2 mM glutamine and 100 U/100 μg/mL penicillin/streptomycin, was applied onto the cells.
- To correct for test material-specific adsorption and/or scattering of light, cell-free test material-containing controls were included in all test runs for all dilution steps.
- Cells were incubated with the test substance for 16 h. For the determination of LDH, GLU, and TNF-α release, cell culture supernatants were sampled after 16 h of incubation.

Examinations

Positive control:

Corundum and Quartz DQ12

Results and discussion

Details on results:

Under cell culture conditions, i.e. in F-12K medium, the H2O dispersed material showed nearly no change in hydrodynamic diameter (Table 2). Importantly, there was a layer of micron-sized agglomerates/aggregates (mostly ≤ 5 μm, few ≤ 15 μm) at the bottom of the cell culture vials. The density of settled agglomerates, which are not included in the PTA measurements, correlated with the administered concentration (Figure, upper panels). Settled aggregates/agglomerates were nearly completely engulfed by NR8383 cells most of which bore colored inclusions (Figure).


The gravitationally settled fraction of Pigment Green 36 was almost completely ingested by alveolar macrophages (NR8383 cells) up to the highest tested concentration of 180 μg/mL. Cells appeared healthy up to the maximum concentration.
Although the pigment was neither cytotoxic (as determined by release of LDH or GLU) nor pro-inflammatory, it induced a dose-dependent release of H2O2, pointing to some cellular activation (Table 1).
Based on the active/passive classification criteria published by Wiemann et al. 2016, a single positive test of the battery of four results in an overall assessment of "passive".

Any other information on results incl. tables

Table 1: In vitro effects of Pigment Green 36 on NR8383 macrophages in comparison to corundum and quartz DQ12 (n=3).

		LDH	GLU			H2O2			TNFα
	[μg/mL]	[% of pos. CTR]	GLU[% of pos. CTR]			[μmol/L]			[pg/mL]
Pigment Green 36	0	19.6 ± 2.6	1.9	±	0.4	0.5	±	0.2	4.2	±	1.1
	22.5	17.0 ± 5.1	1.8	±	1.9	1.0	±	0.1	3.2	±	1.3
	45	20.6 ± 4.0	3.0	±	0.4	1.8	±	0.3	2.4	±	1.8
	90	23.4 ± 4.8	4.0	±	0.7	3.1	±	0.6**	2.6	±	2.1
	180	30.2 ± 4.5	4.0	±	1.3	5.5	±	0.9***	2.3	±	2.1
Corundum	0	20.5 ± 2.0	2.3	±	0.2	0.5	±	0.0	5.2	±	1.4
	22.5	17.6 ± 2.8	2.9	±	0.8	0.7	±	0.0	5.5	±	2.3
	45	23.2 ± 1.6	3.6	±	1.1	0.9	±	0.2	6.1	±	1.9
	90	25.9 ± 2.6	3.9	±	1.2	1.5	±	0.7	6.5	±	2.2
	180	30.2 ± 2.9	3.9	±	0.9	2.8	±	0.7**	6.5	±	1.8
Quartz DQ12	0	20.5 ± 2.0	2.3	±	0.2	0.5	±	0.0	5.2	±	1.4
	22.5	19.0 ± 3.0	1.9	±	0.1	0.8	±	0.1	5.9	±	1.5
	45	31.6 ± 4.8*	4.2	±	1.2	1.0	±	0.1	12.5	±	1.8**
	90	79.9 ± 6.2***	14.7	±	3.2***	1.8	±	0.4	44.4	±	5.0***
	180	120.1 ± 23.0***	31.5	±	10.3***	2.7	±	0.8**	61.5	±	9.7***

Mean values and standard deviations from three independent experiments. LDH: lactate dehydrogenase, GLU: glucuronidase, ROS: reactive oxygen species (H2O2), TNF: tumor necrosis factor α (TNF α ). Values significantly different from cell control are marked by asterisks (*: P ≤ 0.05; **: P ≤ 0.01; ***: P ≤ 0.001). Two-way analyses of variance (ANOVA) and Dunnett's test were used to compare means from the control and treated groups.

Table 2: Hydrodynamic diameters [nm] of Pigment Green 36 in H2O, KRPG, and F-12K medium at a concentration of 18 mg/L

	size (mean)	size (mode)	size (D10)	size (D50)	size (D90)
water	154 ± 1	132.8 ± 4.6	104.1 ± 1.8	139.2 ± 0.7	203.8. ± 4.5
F-12K	151.2 ± 0.2	124.4 ± 4	99.7 ± 0.5	136.1 ± 1.3	201.7 ± 3.6
KRPG	142.4 ± 1.6	124.8 ± 4	79.9 ± 2.3	128.8 ± 1.3	200.4 ± 2.6