Systemic immune cell response in rats after pulmonary exposure to manganese-containing particles collected from welding aerosols

Figures & data

Table 1.  Metal composition and solubility properties of welding fume samples.

Fume samples	Weight % total metals^a	Soluble/insoluble ratio^b
GMA-MS	Fe 72.2%	0.0139
	Mn 21.7%
MMA-HS	Fe 19.3%	0.2182
	Mn 50.9%
	Cr 8.46%
	K 12.1%
	Na 6.73%
	Ni 0.09%

Note: Metal composition was determined in particles suspended in saline by ICP-AES.

^a Relative to all metals analyzed.

^b Soluble metal composition was determined in filtered soluble fraction (supernatant) of particle suspension after overnight incubation at 37°C and centrifugation (Antonini et al., 2010).

Table 2.  Immune cell differential of whole blood after a single welding fume treatment.

Whole blood leukocytes (10^6/ml)	Saline control	GMA-MS (2.0 mg)	MMA-HS (2.0 mg)
Total Leukocytes	8.37 ± 0.68	8.69 ± 1.10	7.50 ± 0.69
Monocytes	0.36 ± 0.05	0.34 ± 0.04	0.35 ± 0.03
PMN	0.91 ± 0.09	2.01 ± 0.29*	1.47 ± 0.15*
Total Lymphocytes	7.10 ± 0.54	6.33 ± 0.80	5.68 ± 0.58
B-Lymphocytes	2.60 ± 0.24	2.44 ± 0.44	2.55 ± 0.33
T-Lymphocytes	4.30 ± 0.32	3.68 ± 0.34	2.92 ± 0.38*
CD4^+ Lymphocytes	2.98 ± 0.21	2.61 ± 0.24	2.08 ± 0.26*
CD8^+ Lymphocytes	1.41 ± 0.12	1.15 ± 0.11	0.91 ± 0.13*

Note: Immune cell differential in whole blood at 1 day after a single intratracheal instillation of 2.0 mg gas metal arc-mild steel (GMA-MS) or manual metal arc-hard-surfacing (MMA-HS) welding fume. Control animals were treated with sterile saline. PMN = polymorphonuclear leukocytes. Values are means ± SE (n = 6).

* Value significantly different from saline control group for particular cell type (p < 0.05).

Table 3.  Lung injury and inflammation in BALF after repeated welding fume treatments.

Lung parameters	Saline control	GMA-MS (0.125 mg)	GMA-MS (2.0 mg)	MMA-HS (0.125 mg)	MMA-HS (2.0 mg)	MnCl2 (0.125 mg)	MnCl2 (2.0 mg)
Lung injury
LDH (U/L)	43 ± 6	89 ± 8^a	163 ± 13^a	106 ± 11^a	807 ± 99^a,b	127 ± 13^a	452 ± 82^a,c
Albumin (mg/ml)	0.10 ± 0.01	0.16 ± 0.01^a	0.25 ± 0.02^a	0.24 ± 0.02^a	0.85 ± 0.10^a,b	0.24 ± 0.02^a	1.14 ± 0.25^a,b
Cellular (10^6)
AM	7.34 ± 0.51	8.48 ± 0.26	17.40 ± 1.40^a	9.23 ± 0.67	21.60 ± 4.20^a	11.06 ± 1.04^a	13.02 ± 0.92^a
PMN	0.04 ± 0.02	0.37 ± 0.03^a	3.78 ± 0.72^a	0.88 ± 0.09^a	41.40 ± 5.61^a,b	5.79 ± 1.44^a	13.98 ± 3.0^a,c
Lymph	0.02 ± 0.01	0.12 ± 0.01^a	0.94 ± 0.40^a	0.26 ± 0.02^a	3.28 ± 0.27^a,b	0.39 ± 0.05^a	0.73 ± 0.32^a
Chemokines (pg/ml)
MCP-1	37 ± 19	36 ± 13	51 ± 8	16 ± 7	751 ± 116^a,b	46 ± 7	567 ± 189^a,b
MIP-2	460 ± 39	431 ± 23	604 ± 14^a	553 ± 24	1035 ± 35^a,b	666 ± 69^a	1047 ± 32^a,b
TNFα	21 ± 4	23 ± 3	18 ± 1	19 ± 3	48 ± 2^a,b	32 ± 3	61 ± 14^a,b
IL-6	267 ± 71	171 ± 12	127 ± 30	124 ± 18	639 ± 102^a,b	301 ± 79	1011 ± 239^a,b
Antibody
IgG (pg/ml)	880 ± 102	1070 ± 195	1908 ± 429	3004 ± 790^a	9663 ± 6307^a	3908 ± 1108^a	4078 ± 1979^a

Note: Biochemical and cellular parameters measured in bronchoalveolar lavage fluid (BALF) at 1 day after repeated intratracheal instillations of 0.125 or 2.0 mg of gas metal arc-mild steel (GMA-MS) and manual metal arc-hard-surfacing (MMA-HS) welding fume or MnCl₂ once a week for 7 weeks. Control animals were treated with sterile saline.

LDH, lactate dehydrogenase; AM, alveolar macrophages; PMN, polymorphonuclear leukocytes; Lymph, lymphocytes. Values are means ± SE (n = 5–6).

^a Value significantly different from saline control when comparing groups within a parameter; ^b value significantly greater than that noted in all other groups for the given parameter; ^c value significantly greater than that noted in all other groups except the MMA-HS 2.0 mg group for the given parameter (p < 0.05).

Figure 1.  Systemic response; repeated treatment. Total (a) leukocytes, (b) monocytes, (c) PMN, and (d) lymphocytes in whole blood at 1 day after repeated intratracheal instillations of 0.125 or 2.0 mg of gas metal arc-mild steel (GMA-MS) and manual metal arc–hard-surfacing (MMA-HS) welding fume or MnCl₂ once a week for 7 weeks. Control animals were treated with sterile saline. Values are means ± SE (n = 5–6). * Value significantly different from saline control group for a particular cell type (p < 0.05).

Figure 2.  Systemic response; repeated treatment. (a) B-lymphocytes, (b) T-lymphocytes, (c) CD4⁺ lymphocytes, and (d) CD8⁺ lymphocytes in whole blood at 1 day after repeated intratracheal instillations of 0.125 or 2.0 mg of gas metal arc-mild steel (GMA-MS) and manual metal arc-hard-surfacing (MMA-HS) welding fume or MnCl₂ once a week for 7 weeks. Control animals were treated with sterile saline. Values are means ± SE (n = 5–6). * Value significantly different from saline control group for a particular cell type (p < 0.05).

Antonini, J. M., Roberts, J. R., Chapman, R., Soukup, J. M., Ghio, A. J., and Sriram, K. 2010. Pulmonary toxicity and extra-pulmonary tissue distribution of metals after repeated exposure to different welding fumes. Inhal. Toxicol. 22:805–816.

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