One of the major lacunae in the preclinical drug discovery is the lack of an animal model which recapitulates the pathophysiology as well as the behavioural symptoms of clinical Parkinson’s disease (PD). The aim of the present study was to compare the effects of unilateral and bilateral stereotaxic injection of rotenone to develop an optimised PD model. In the present study, 20 adult male Sprague Dawley rats (200-250 g) were assigned to four groups with 5 animals in each. These groups comprised of Sham, vehicle control, unilateral and bilateral rotenone (12 µg/µl) injection in Substantia nigra (SN). The behavioural parameters  concerning the grip strength and neuromuscular coordination was examined by means of wire hang test. Then, we analysed biochemical parameters involving mitochondrial complex I inhibition and oxidative stress (Reduced GSH, Superoxide dismutase). The results were correlated with the histopathological assessment determining the neuronal death. Both unilateral and bilateral administration resulted in a decrease in latency to fall with the loss in grip being more severe in the bilateral group. The mitochondrial complex I inhibition due to rotenone resulted in the significant increase in oxidative stress. The histopathological analysis revealed severe neuronal apoptosis in substantia nigra suggesting neurodegeneration, which was more evident in bilateral groups. Both unilateral and bilateral administration result in induction of the symptoms and pathophysiological changes. However, bilateral administration proved to be a better delivery strategy for the development of PD animal models.

1.             Cannon JR, Greenamyre JT. Neurotoxic in vivo models of Parkinson’s disease recent advances. Prog Brain Res. 2010 Jan 1;184. doi: 10.1016/S0079-6123(10)84002-6, PMID 20887868.

2.             Bové J, Perier C. Neurotoxin-based models of Parkinson’s disease. Neuroscience. 2012 Jun 1;211:51-76. doi: 10.1016/j.neuroscience.2011.10.057, PMID 22108613.

3.             Xiong N, Huang J, Zhang Z, Zhang Z, Xiong J, Liu X, Jia M, Wang F, Chen C, Cao X, Liang Z, Sun S, Lin Z, Wang T. Stereotaxical infusion of rotenone: a reliable rodent model for Parkinson’s disease. PLOS ONE. 2009 Nov 18;4(11):e7878. doi: 10.1371/journal.pone.0007878, PMID 19924288.

4.             Cannon JR, Tapias V, Na HM, Honick AS, Drolet RE, Greenamyre JT. A highly reproducible rotenone model of Parkinson’s disease. Neurobiol Dis. 2009 May 1;34(2):279-90. doi: 10.1016/j.nbd.2009.01.016, PMID 19385059.

5.             Saravanan KS, Sindhu KM, Mohanakumar KP. Acute intranigral infusion of rotenone in rats causes progressive biochemical lesions in the striatum similar to Parkinson’s disease. Brain Res. 2005 Jul 12;1049(2):147-55. doi: 10.1016/j.brainres.2005.04.051, PMID 15936733.

6.             Moreira CG, Barbiero JK, Ariza D, Dombrowski PA, Sabioni P, Bortolanza M, Da Cunha C, Vital MA, Lima MM. Behavioral, neurochemical and histological alterations promoted by bilateral intranigral rotenone administration: a new approach for an old neurotoxin. Neurotox Res. 2012 Apr 1;21(3):291-301. doi: 10.1007/s12640-011-9278-3, PMID 21953489.

7.             Paxinos G, Watson C. The rat brain in stereotaxic coordinates: hardcover edition. Elsevier; 2006 Nov 2.

8.             Rabl R, Horvath A, Breitschaedel C, Flunkert S, Roemer H, Hutter-Paier B. Quantitative evaluation of orofacial motor function in mice: the pasta gnawing test, a voluntary and stress-free behavior test. J Neurosci Methods. 2016 Dec 1;274:125-30. doi: 10.1016/j.jneumeth.2016.10.006, PMID 27746230.

9.             Li X. Improved pyrogallol autoxidation method: a reliable and cheap superoxide-scavenging assay suitable for all antioxidants. J Agric Food Chem. 2012 Jun 27;60(25):6418-24. doi: 10.1021/jf204970r, PMID 22656066.

10.           Smith IK, Vierheller TL, Thorne CA. Assay of glutathione reductase in crude tissue homogenates using 5, 5′-dithiobis (2-nitrobenzoic acid). Anal Biochem. 1988 Dec 1;175(2):408-13. doi: 10.1016/0003-2697(88)90564-7, PMID 3239770.

11.           Reilly CA, Aust SD. Measurement of lipid peroxidation. Curr Protoc Toxicol. 2001;Chapter(2):Unit 2.4. doi: 10.1002/0471140856.tx0204s00. PMID 23045044.

12.           Spinazzi M, Casarin A, Pertegato V, Salviati L, Angelini C. Assessment of mitochondrial respiratory chain enzymatic activities on tissues and cultured cells. Nat Protoc. 2012 Jun;7(6):1235-46. doi: 10.1038/nprot.2012.058, PMID 22653162.

13.           Alam M, Schmidt WJ. Rotenone destroys dopaminergic neurons and induces parkinsonian symptoms in rats. Behav Brain Res. 2002 Oct 17;136(1):317-24. doi: 10.1016/S0166-4328(02)00180-8, PMID 12385818.

14.           Aartsma-Rus A, van Putten M. Assessing functional performance in the mdx mouse model. J Vis Exp. 2014;85(85):e51303. doi: 10.3791/51303, PMID 24747372.

15.           Hutter-Saunders JA, Gendelman HE, Mosley RL. Murine motor and behavior functional evaluations for acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication. J Neuroimmune Pharmacol. 2012 Mar 1;7(1):279-88. doi: 10.1007/s11481-011-9269-4, PMID 21431472.

16.           Sherer TB, Betarbet R, Testa CM, Seo BB, Richardson JR, Kim JH, Miller GW, Yagi T, Matsuno-Yagi A, Greenamyre JT. Mechanism of toxicity in rotenone models of Parkinson’s disease. J Neurosci. 2003 Nov 26;23(34):10756-64. doi: 10.1523/JNEUROSCI.23-34-10756.2003, PMID 14645467.

17.            Sindhu KM, Saravanan KS, Mohanakumar KP. Behavioral differences in a rotenone-induced hemiparkinsonian rat model developed following intranigral or median forebrain bundle infusion. Brain Res. 2005 Jul 27;1051(1-2):25-34. doi: 10.1016/j.brainres.2005.05.051, PMID 15992782.