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Results: 7

Figure 3

Figure 3. Methylene blue coadministration attenuates the penumbral striatal oxidative stress elicited by intrastriatal rotenone. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

In the unilateral lesion model, the perilesional DHE signal observed in the rotenone (Rot)-treated hemispheres (ipsilateral) was significantly higher than that of non-treated hemispheres (contralateral), whereas no interhemispheric difference was observed in the Rot/MB group. * = different from contralateral striatum, p < 0.05.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.
Figure 4

Figure 4. Effects of methylene blue co-administration on rotenone-induced hypometabolism in the striatum. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

At Bregma level 0.3 mm, the striatum (CPu) in the infused hemisphere was subdivided in three zones: a) lesion core, which matched the region of highest structural damage in Nissl-stained sections, b) lesion penumbra, and c) spared ipsilateral striatum. MB co-administration counteracted the hypometabolism in the striatal lesion core induced by rotenone (Rot). MB also prevented the compensatory changes in metabolic activity caused by Rot in the lesion penumbra and the contralateral striatum (Contra). Ipsi = spared ipsilateral striatum. * = p < 0.05.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.
Figure 1

Figure 1. Energy hypometabolism precedes striatal neurodegeneration. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

(A) A Nissl-stained rat brain coronal hemisection at Bregma level +0.3 mm shows very little evidence of ipsilateral striatal structural damage 1 hr post-Rotenone (Rot) infusion. Only mild hydrocephalus was detected (arrow). (B) At 1 hr, however, cytochrome oxidase activity histochemistry revealed an area of striatal hypometabolism (asterisk) at the same Bregma level in the same subject. (C and D) No evidence of structural lesion or striatal hypometabolism was evident in vehicle-treated subjects after 7 days. Scale bar = 1 mm.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.
Figure 5

Figure 5. Rotenone induces complex I dysfunction in striatal mitochondria not reversible by methylene blue. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

Compared to control, striatal mitochondria exposed to rotenone (Rot) showed a 63% decrease in complex I activity after only 3 min. MB concentrations estimated to be similar to those reached after in vivo infusion (0.5 µM) did not prevent Rot effects. High MB concentrations (5 µM and 50 µM) were also ineffective at preventing the Rot-induced complex I activity inhibition, which rules out the possibility that the neuroprotective effects of MB are due to a direct interaction with rotenone molecules or to blockade of Rot’s binding site at complex I. * = different than control, p < 0.05.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.
Figure 7

Figure 7. Effects of methylene blue co-administration on the neuronal damage induced by bilateral intrastriatal infusions of rotenone. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

(A) Nissl-stained forebrain coronal section of a subject receiving bilateral intrastriatal infusions of rotenone alone (Rot, left hemisphere) and rotenone plus MB (Rot/MB, right hemisphere). The Rot-treated hemisphere showed an ellipsoidal mid-striatal lesion, characterized by a cavity of liquefactive necrosis surrounded by a rim of reactive gliosis (asterisk). The lesion was accompanied by callosal damage and hydrocephalus (black arrow). In contrast, the MB co-treated hemisphere showed significantly less striatal damage, featuring a comparatively smaller lesion limited to the corpus callosum (white arrow). (B) Within-subject mean lesion volume difference. MB co-treatment significantly decreased the total striatal lesion volume, compared to the Rot alone-treated hemisphere. ** = p < 0.01.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.
Figure 2

Figure 2. Effects of methylene blue on rotenone-induced striatal damage in unilaterally infused rats. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

(A and B) Intrastriatal infusion of rotenone alone (Rot) produced a large area of liquefactive necrosis surrounded by gliosis (asterisk) and accompanied by mild ipsilateral lateral ventricle enlargement (arrow). The toxic effects of Rot appeared to be attenuated in those rats receiving a combined intrastriatal infusion of Rot/MB. (C and D) Peri-lesional oxidative stress in situ was measured in micrographs of DHE-stained sections. An increased signal was detected in the striatum adjacent to the lesion in the Rot-treated subjects. Conversely, the DHE signal was comparatively lower in penumbral regions in Rot/MB-treated subjects. Epifluorescence microscopy, 50X. (E and F) Cytochrome oxidase histochemistry-stained forebrain coronal sections from the same subjects depicted in A and B show corresponding regions of striatal hypometabolism that is less severe in the Rot/MB-treated subject.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.
Figure 6

Figure 6. Methylene blue enhances the functional connectivity between regions involved in motor control. From: STRIATAL NEUROPROTECTION WITH METHYLENE BLUE.

The cytochrome oxidase activity data from the lesioned hemispheres were applied to an anatomical network model of motor control, and patterns of functional connectivity were determined based on interregional metabolic activity correlations. The vehicle-injected control group was used as a reference for functional connectivity in the network of interest. The striatal damage induced by rotenone (Rot) resulted in a general functional disconnection (thinner arrows) in the basal ganglia-thalamocortical motor loop, with a pattern characterized by 1) decoupling between the subthalamic nucleus (STh) and the substantia nigra reticulata (SNr), 2) decoupling between thalamic regions (VA/VL) and the secondary motor cortex (M2), 3) decoupling between M2 and the striatum (CPu), and 4) emergence of a strong functional correlation between CPu and SNr (i.e. descending striatonigral pathway). MB co-treated subjects (Rot/MB) showed strengthening of functional influences in the indirect striatal, thalamocortical and corticostriatal pathways compared to Rot, a pattern suggestive of MB-induced network normalization that was similar to control. Arrow direction is given by the anatomical connectivity model and arrow thicknesses represent the magnitude of the interregional correlation coefficients (r) (i.e. an index of the degree of functional coupling). Thicker lines represent higher functional coupling, whereas thinner lines represent lower coupling. Solid arrows represent positive (+r), whereas segmented arrows represent negative (−r) interregional metabolic activity correlations. * = significant difference from control. • = significant difference from Rot group.

Julio C. Rojas, et al. Neuroscience. ;163(3):877-889.

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