Table 1.

Experimental results demonstrating the pathological crosstalk between the gut and brain.

Animal Model of IBD	Effect on the CNS	Refs.
TNBS-induced colitis in rabbit	Increased blood-brain barrier permeability	Hathaway et al. [32]
TNBS-induced colitis in rat	Elevated blood-brain barrier permeability and reduced endothelial barrier antigen expression	Natah et al. [33]
	Increased interleukin IL-6 expression in the hypothalamus and cerebral cortex	Wang et al. [34]
DSS-induced colitis in mouse	Elevated TNF-α, IL-1ß, and IL-6 expression in the substantia nigra	Villarán et al. [35]
	Increased TNF-α and IL-6 expression in the cortex and decreased TJ protein occludin and claudin-5 in the brain	Han et al. [36]
	Increased nigral level of IL-1ß and dopaminergic neuron death	Garrido Gil et al. [37]
	Increased COX-2 expression in the hippocampus and hypothalamus	Do et al. [38]
	α-syn aggregation in the midbrain	Grathwohl et al. [39]
	Microglial polarization into M1 and M2 phenotype in the medial prefrontal cortex	Sroor et al. [40]
	Increased IL-1ß, IL-6, TNF-α and IL-10 expression in the hippocampus	Gampierakis et al. [41]
	NLRP3 activation, amyloid plaque accumulation, and apoptosis in hippocampus, Cortex	He et al. [42]
	Elevated IL-1ß and TNF-α expression in the brain	Talley et al. [43]
	Increased microglia and astrocyte activation and loss of dopaminergic neurons in the substantia nigra pars compacta after PD inducing MPTP treatment	Gil-Martínez et al. [44]
	Increased neurotoxic effect of MPTP treatment	Houser et al. [45]