Table 3.

Animal Models in Cr (VI) Neurotoxicology Studies

Species (Gender)	Cr Compound	Exposure Route	Dose(s)	Duration	Cr Level Reported (ug/g)	Method of Detection	Reference
Rabbit (M)	K₂Cr₂O₇	i.p.	2 mg/kg	3 and 6 weeks	1.6 and 1.3	Not reported	Mathur et al., 1977
Wistar rat (M)	Na₂CrO₄	d.w.	700 mg/L	28 d	N/A		Diaz-Mayans et al., 1986
		d.w.	70 mg/L	7 d	N/A
		i.p.	2 mg/kg	24 h	N/A
Swiss mice (F)	K₂Cr₂O₇	d.w.	25 mg/kg	1–3 d	0.5	AAS	Travacio et al., 2000
C57BL/6Ntac (F)	Na₂CrO₄	Oral	95 mg/kg	24 h	N/A		Bagchi et al., 2001
C57BL/6TSG p53 (M) (p53 deficient)	Na₂CrO₄	Oral	95 mg/kg	24 h	N/A		Bagchi et al., 2001
Albino mice (M) (ddY strain)	K₂Cr₂O₇	i.p.	20 mg/kg	15 min, 3 h, 24 h	0.28 ± 0.13, 0.31 ± 0.27, 0.15 ± 0.03	AAS	Ueno et al., 2001
C57BL/6Ntac (F)	Na₂CrO₄	Oral	1.9, 19, 95 mg/kg	0, 12, 24, 48, 72, 96 h	N/A		Bagchi et al., 2002
Wistar rats (M)	K₂Cr₂O₇	d.w.	500 ppm = 73.05 mg Cr/kg/d	30 d	Pituitary = 0.64 Hypothalamus = 0.059	AAS	Quinteros et al., 2007
Wistar rats (M)	K₂Cr₂O₇	d.w.	100 ppm = 11.6 mg Cr/kg/d	30 d	Pituitary = 0.274 Hypothalamus = 0.026	AAS	Nudler et al., 2009
Swiss albino mice (M)	K₂Cr₂O₇	i.p.	8.0 mg/kg	12h	1.40	ICP-MS	Döker et al., 2010
Wistar rats (F)	K₂Cr₂O₇	d.w.	700 ppm	21 d	N/A		Soudani et al., 2012
Wistar rats (M)	K₂Cr₂O₇	i.p.	15 mg/kg	24 h	N/A		García-Niño et al., 2015
Albino Wistar rats (M)	K₂Cr₂O₇	i.p.	15 mg/kg	24 h	5.4	AAS	Salama et al., 2016
Albino Wistar rats (M)	K₂Cr₂O₇	i.n.	0.5, 1, 2 mg/kg	24 h	0.13, 0.41, 0.92		Salama et al., 2016
Rockfish, S. schlegelii	K₂Cr₂O₇	Diet	30, 60, 120, 240 mg/kg	2 or 4 weeks	N/A		Kim and Kang, 2016
Guinea pig (M)	K₂Cr₂O₇	i.p.	60 μg/g/kg	3 weeks	N/A		Fahmy, 2017
Wistar rat (M)	K₂Cr₂O₇	i.p.	2 mg/kg	30 d	N/A		Mahmoud and El-Twab, 2017
Wistar rat (M)	Cr₂O₃ NP	Oral w/ cannula	0.5 or 2 mg/kg	24 h, 7 d, 14 d	N/A		Fatima et al., 2017
Wistar rat (M)	Cr(OH)₃ NP	Intratracheal instillation	2 mg/kg welding fumes w/ Mn and Fe	once a day, 5x/week, for 4 weeks	N/A		Máté et al., 2017
Hyland brown chicken (M)	K₂Cr₂O₇	d.w.	(6% LD₅₀)	14, 28, 42 d	N/A		Hao et al., 2017
Swiss mice, nulliparous (F)	Tannery effluent	Environmental sludge	500 mL (containing 859 mg/L Cr)	2 h/d, 20 d	N/A		Estrela et al., 2017
Sprague-Dawley rats (M)	K₂Cr₂O₇	Oral	25 mg/kg	6 weeks	N/A		Abu Zeid et al., 2018
Zebrafish (Danio rerio)	K₂Cr₂O₇	Water	3, 271, 2700 μg/g/L	24 h	N/A		Heffern et al., 2018
Drosophila melanogaster	K₂Cr₂O₇	Diet	5, 10, or 20 μg/g/mL	24 h or 48h	N/A		Singh and Chowdhuri, 2018
Wistar rats (M)	K₂Cr₂O₇	i.p.	14 mg/kg (0.5 LD50)	24 h	N/A		Iztleuov et al., 2018
Chicken	K₂Cr₂O₇	Oral	22.14 mg/kg	14, 28, 42 d	0.1669 ± 0.0041, 0.2520 ± 0.0075, 0.2918 ± 0.0040	ICP-MS	Zhu et al., 2018
Sprague-Dawley rats (F)	K₂CrO₄	Oral gavage	10 mg/kg	2 weeks	N/A		Sarica et al., 2019
Zebrafish (Danio rerio)	K₂CrO₄	Water	2 mg Cr/L	1, 7, 15, 30, or 60 d	N/A		Shaw et al., 2020
Japanese Quail (Coturnix japonica)	K₂Cr₂O₇	d.w.	1.2, 2.4 μg/mL	20 d	10.58 ± 4.5 10.62 ± 6.94	USEPA Methods 3060A and 7196A: alkaline digestion and colorimetric spectrophotometry	Suljević et al., 2021
Wistar rats (M)	K₂Cr₂O₇	i.n.	0.125, 0.25, 0.5 mg/kg/d	5 d per week, 2 weeks and 2 months	N/A		Hegazy et al., 2021

NP = nanoparticles; i.p. = intra peritoneal; d.w. = drinking water; i.p. = intra peritoneal; d.w. = drinking water; i.n. = intra-nasal AAS = atomic absorption spectrometry; ICP-MS = inductively coupled plasma-mass spectrometry; N/A = not assessed