Table 3.

Summary of the main studies relating the impact of vitamin A pathway enhancement (dietary intake, vitamin A derivatives, or receptors ligands) in Parkinson’s disease rodent models

PD model	Supplemen-tation	in vitro/in vivo	Behavioral tests	Motor behavior*	Survival of SNc neurons*	SNc proteins changes*	Striatal proteins changes*	α-synuclein*	Neuroinfla.*	Ox. stress*	Study
Mice MPTP; 6-OHDA; AAV α-synuclein	NURR1:RXRα activator	Both	Rotarod	↗↗	↗↗	TH, DA ↗↗	TH ↗↗				[75]
MPTP mice	RA in striatum	in vivo			↗↗	TH, Pitx3, NURR1 ↗↗	TH, NURR1 (old mice) ↗↗				[77]
6-OHDA rats	9-cis RA (icv)	Both	Rotational test	↗	↗↗	TH ↗↗	DA release &clearance ↗↗				[78]
Metamphet. in rats	9-cis RA (icv)	Both	Motor activity	↗	↗↗		TH ↗				[79]
6-OHDA on mouse primary cultures	RXR agonists	in vitro			↗						[81]
α-synuclein	Vitamin A and β-carotene	in vitro						↘ α-synuclein fibrils			[82]
A53T mice	DHA; RXR over expression; 9-CIS RA	in vitro						↗ oligomers			[83]
6-OHDA rats	vit. A	in vivo	Rotarod	No effect	No effect	TH =	TH =		Iba-1↘ GFAP ↗	TNF-α, Il-1β ↘	[86]

^*compared to PD model without supplementation.