Neurotoxicity and inflammation induced by individual and combined exposure to iron oxide nanoparticles and silver nanoparticles

Figures & data

Figure 1. Stained agarose gel electrophoresis of genomic DNA of brain. Control group (Lane 1 & 2) showed very low or undetectable DNA laddering (DNA fragmentation) compared to DNA marker (Lane 8, 1 kb). Silver nanoparticles alone (Lane 3 & 4) revealed DNA fragmentations which appear as DNA smearing. Iron oxide nanoparticles (Lane 5 & 6) showed very low brain genomic DNA fragmentation. The combination group (Lane 7) showed massive DNA fragmentations which appear as DNA smearing compared to DNA marker (Lane 8).

Table 1. The initial and final body weight, weight gain and brain weights (grams) of male rats exposed to iron oxide nanoparticles (Fe₂O₃NPs) and/or silver nanoparticles (AgNPs).

	Experimental groups
Parameter	Control	Fe2O3NPs	AgNPs	Fe2O3NPs+ AgNPs
I.B.W.	165.0±2.79^a	168.5±2.59^a	171.0±2.21^a	171.5±3.42^a
F.B.W.	242.0±6.36^a	213.0±3.67^b	219.0±3.32^b	198.5±2.84^c
B.W.G	77.0±4.16^a	44.5±3.11^b	48.0±2.91^b	27.0±1.70^c
Brain weight	1.63±0.04^a	1.54±0.05^b	1.52±0.05^b	1.48±0.08^c

Notes: Data presented as Mean±SE. Mean values within a row not sharing a common superscript letters (a, b, c) were significantly different, p < 0.05. (I.B.W = Initial body weight, F.B.W = Final body weight, B.W.G = Body weight gain).

Figure 2. The expression of mtTFA (A) and PGC-1α (B) in brain tissues of rats exposed to iron oxide nanoparticles (Fe₂O₃NPs) and/or silver nanoparticles (AgNPs) (data presented as Mean±SE. Mean values that not sharing a common small letters (a,b,c) are significantly different, p < 0.05).

Figure 3. The levels of p53 (A), TNF-α (B) and IL-6 (C) in brain tissues of rats exposed to iron oxide nanoparticles (Fe₂O₃NPs) and/or silver nanoparticles (AgNPs) (data presented as Mean±SE. Mean values not sharing a common small letters (a,b,c) are significantly different, p < 0.05).

Table 2. Brain and plasma activities of acetylcholine esterase (AchE) and levels of acetylcholine (Ach), norepinephrine (NE), sertonine, and dopamine in male rats exposed to iron oxide nanoparticles (Fe₂O₃NPs) and/or silver nanoparticles (AgNPs).

	Experimental groups
Parameter	Control	Fe2O3NPs	AgNPs	Fe2O3NPs+ AgNPs
BrainACh (n mol/mg protein)	96±4.1^c	186±6.1^b	254±6.5^b	304±10.7^a
AChE (U/mg protein)	44±1.5^a	25±1.5^c	29±1.9^b	20±0.9^d
NE (pg/g tissue)	0.12±0.01^c	0.21±0.02^b	0.20±0.01^b	0.36±0.03^a
Serotonin (ng/g tissue)	189±3.5^a	111±3.5^c	131±3.5^b	84±3.5^d
Dopamine (ng/g tissue)	201±5.36^a	133±4.62^b	112±3.61^c	72±3.48^d
Plasma ACh(nmol/ml)	75±3.8^c	106±7.3^b	103±5.5^b	153±9.2^a
AChE (U/ml)	39±2.03^a	26±2.65^c	20±2.03^b	13±1.20^d
NE (pg/ml)	0.09±0.01^c	0.14±0.01^b	0.16±0.01^b	0.22±0.02^a
Serotonin (ng/ml)	310±7.8^a	212±6.5^c	257±7.4^b	123±6.4^d
Dopamine (ng/ml)	173±5.6^a	101±1.5^c	131±6.1^b	79±4.1^d

Notes: Data presented as Mean±SE. Mean values within a row not sharing a common superscript letters (a, b, c, d) were significantly different, p < 0.05.

Table 3. Brain levels of thiobarbituric acid-reactive substances (TBARS), nitric oxide (NO), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione peroxidase (GPX) and total antioxidant capacity (TAC) in male rats exposed to iron oxide nanoparticles (Fe₂O₃NPs) and/or silver nanoparticles (AgNPs).

	Experimental groups
Parameter	Control	Fe2O3NPs	AgNPs	Fe2O3NPs+ AgNPs
TBARS	38±0.5^a	53±1.9^b	56± 1.8^b	65±1.6^c
(nmole/g tissue)
NO	43.9±1.27^d	66.0±1.10^c	76.4±1.65^b	115.8±1.73^a
(µmol/g tissue)
GSH	6.6±0.17^a	5.0±0.13^b	5.1±0.15^b	3.8±0.10^c
(nmol/g tissue)
SOD	43.5±1.70^a	28.3±1.43^b	29.0±1.87^b	22.9±0.81^c
(mU/mg protein)
CAT	37.8±1.43^a	26.0±1.37^b	23.8±0.83^b	19.0±1.22^c
(U/mg protein)
GST	0.64±0.027^a	0.52±0.024^b	0.49±0.015^b	0.33±0.017^c
(U/mg protein)
GPX	44.1±2.39^a	32.2±1.67^b,c	33.2±1.35^b	27.5±1.65^c
(mU/mg protein)
TAC	19.84±0.10^a	16.85±0.20^b	15.40±0.74^b	12.73±0.11^c
(µmol/g tissue)

Notes: Data presented as Mean ±SE. Mean values within a row not sharing a common superscript letters (a, b, c) were significantly different, p < 0.05.

Figure 4. Light micrograph of brain of male rats. Control group (a) showed normal glial. Iron oxide nanoparticles group (b) revealed pericellular edema, dilation of blood vessels, vacuolization and pyknosis of nuclei. Silver nanoparticles group (c) revealed mild neuronal degeneration and pyknotic nuclei, pericellular edema, dilation of blood vessels and neuronal vacuolization. Combination group of iron oxide nanoparticles and silver nanoparticles (d) revealed neuronal degeneration and pyknotic nuclei, pericellular edema, dilation of blood vessels and neuronal vacuolization (H & E; X 40).

Table 4. Quantitative analysis of brain histology of male rats exposed to iron oxide nanoparticles (Fe₂O₃NPs) and/or silver nanoparticles (AgNPs).

	Quantitative analysis	Control	Fe2O3NPs	AgNPs	Fe2O3NPs+ AgNPs
1	Pericellular edema	−	+ +	+	++ +
2	Dilation of blood capillary with congestion.	−	+ +	+	+ + +
3	Neuronal degeneration with pyknosis of the nuclei	−	+ +	+	+ + +
4	Vacuolization	−	+ +	+	+ + +

Note: (−) No change, (+) mild change, (++) moderate change, (+++) moderate to marked change, (++++) marked change.