Table 2.

Drosophila model of Parkinson’s disease.

	DROSOPHILA MODEL		STAGE OF NEUROPATHOLOGICAL ASSESMENT	ASSAY EMPLOYED FOR NEUROPATHOLOGICAL ASSESSMENT	KEY ACHIEVEMENTS	REFERENCES
DROSOPHILA ORTHOLOGS OF HUMAN GENES	Mutants with alterations in the PINK1 gene and reduction of PINK1 expression specifically in dopamine neurons		Adult	Measurement of lifespan, immunostaining for tyrosine hydroxylase (TH), chemotaxis assay, dopamine enzyme immunoassay, high-performance liquid chromatography (HPLC) for dopamine tissue and dopamine levels	Showed the link between PINK1 mutations and dopamine neuron degeneration, mimicking Parkinson’s disease pathology	[100], [101]
	Mutants with alterations in the parkin gene		Adult	Immunostaining for TH and conducting a climbing assay	Established the effects of parkin gene alterations on dopaminergic neuron health and motor function, aiding in Parkinson’s disease studies	[102]
	LRRK2 mutants		Adult	Assessment of climbing ability and immunostaining for TH	Explored the impact of LRRK2 mutations on dopaminergic neuron function and motor deficits relevant to Parkinson’s disease	[103]
	Reduction of HtrA2 expression specifically in dopamine neurons and photoreceptor cells		Adult	Assessment of lifespan, climbing ability, and scanning electron microscopy (SEM) for eye morphology	Highlighted HtrA2’s role in maintaining dopaminergic and photoreceptor cell health, contributing to insights on neurodegenerative diseases	[104]
	Mutations in both CG31414 and CG31148 genes, known as double heterozygous GBA mutants		Adult	Measurement of lifespan, immunostaining for TH, and climbing assay.	Demonstrated the effects of GBA mutations on lifespan and dopaminergic function, linking to Parkinson’s disease	[105]
	Mutations in the DJ-1 gene subjected to exposure to rotenone, hydrogen peroxide, and paraquat		Adult	Measurement of lifespan and immunostaining for TH	Established the role of DJ-1 in oxidative stress responses and dopaminergic neuron survival, aiding in Parkinson’s disease research	[106]
	Overexpression of dUCH specifically in photoreceptor cells and knockdown of dUCH specifically in dopamine neurons		Larva, Pupa, Adult	SEM for examining eye morphology, immunostaining for activated-Caspase 3 and TH	Examined the effects of dUCH expression alterations on neurodegeneration in dopaminergic and photoreceptor cells	[107]
OVEREXPRESSION OF HUMAN TRANSGENES	Simultaneous expression of Tau and Alpha-Synuclein (α-syn)		Larva, Adult	Immunostaining for activated-caspase 3, NMJ morphology, immunostaining for TH, SEM for adult eye morphology	Showed the synergistic effects of Tau and α-syn on neurodegeneration, providing a model for studying combined pathologies	[108]
	Expression of LRRK2 and LRRK2-G2019S-2 in pan-neuronal cells, photoreceptor cells and dopamine neurons		Adult	Lifespan measurement, climbing assay, photoreceptor morphology, TEM, immunostaining for TH, actometer test	Identified the role of LRRK2 mutations in dopaminergic neurodegeneration, aiding in understanding Parkinson’s disease	[109]
	Increased expression of Pael-R specifically in dopamine neurons		Adult	Immunostaining for TH	Established the link between Pael-R overexpression and dopaminergic neuron degeneration, providing a model for Parkinson’s disease	[109]
EXPOSURE TO TOXINS	Rotenone		Adult	Immunostaining for TH, climbing assay	Demonstrated the role of environmental toxins like Rotenone in Parkinson’s disease pathogenesis	[110]
	Paraquat		Adult	Immunostaining for TH, climbing assay, lifespan, jumping assay, dopamine levels	Confirmed the role of oxidative stress in Parkinson’s disease, showing how Paraquat induces dopaminergic neuron degeneration	[111]; [112]