Modest effect on plaque progression and vasodilatory function in atherosclerosis-prone mice exposed to nanosized TiO2

Table 2 Endothelium dependent (acetylcholine: ACh, and calcitonin-gene related peptide: CGRP) and independent (nitroglycerin: NTG, and felodipine: FD) vasodilatory function in ApoE^-/- mice after intratracheal instillation of TiO₂ particles or control solution (90% saline and 10% BAL fluid).

Exposure i.t. instillation	Drug	- tempol		+ tempol
		EC ₅₀ (nM)	E _max (%)	EC ₅₀ (nM)	E _max (%)
Control	ACh	160.4 ± 65.0	56.7 ± 3.59	105.9 ± 35.6	31.2 ± 5.39*
fTiO₂		207.7 ± 75.9	51.8 ± 4.98	107.5 ± 48.9	39.9 ± 6.23
pTiO₂		222.3 ± 67.6	46.1 ± 3.92	49.3 ± 7.73	53.5 ± 7.31^#
nTiO₂		101.7 ± 32.1	54.7 ± 4.99	64.2 ± 11.0	42.1 ± 7.43
Control	CGRP	8.7 ± 2.1	87.9 ± 2.69	13.3 ± 2.73	72.4 ± 5.82*
fTiO₂		11.6 ± 2.1	82.7 ± 3.23	15.2 ± 2.28	73.6 ± 3.23
pTiO₂		9.4 ± 0.90	90.0 ± 1.57	11.1 ± 0.53	78.2 ± 3.34
nTiO₂		14.8 ± 2.1	80.4 ± 6.20	14.5 ± 2.42	70.9 ± 6.96
Control	NTG	23.8 ± 3.96	69.8 ± 3.41	68.7 ± 12.4*	60.3 ± 2.36*
fTiO₂		25.8 ± 4.63	66.5 ± 2.87	64.1 ± 16.9	60.3 ± 3.37
pTiO₂		25.30 ± 8.26	69.8 ± 2.97	41.7 ± 5.3	65.6 ± 4.30
nTiO₂		21.3 ± 4.43	67.3 ± 3.03	55.1 ± 20.9	64.4 ± 2.09
Control	FD	10.4 ± 2.70	84.7 ± 3.74	7.57 ± 1.58	85.9 ± 2.69
fTiO₂		6.67 ± 1.05	84.6 ± 4.62	5.96 ± 0.94	89.7 ± 2.36
pTiO₂		6.55 ± 0.90	84.8 ± 1.87	5.26 ± 1.04	86.1 ± 1.81
nTiO₂		7.82 ± 1.79	90.6 ± 2.70	8.58 ± 2.95	83.5 ± 2.83

All measurements were done in both absence and ex vivo presence of the SOD mimic, tempol. Data are expressed as means ± SEM (n = 10-11).
^# Interaction between the treatment with particles and tempol (P < 0.05, ANOVA). The post-hoc analysis showed lower E_max values in animals intratracheally instilled with control solution, whereas there are higher E_max values in ex vivo tempol treated vessels of the animals exposed to pTiO₂ particles. *P < 0.05 (ANOVA) compared to E_max values in segments that were not treated with tempol.

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