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Experimentally induced diabetes causes glial activation, glutamate toxicity and cellular damage leading to changes in motor function.

Nagayach A, Patro N, Patro I - Front Cell Neurosci (2014)

Bottom Line: Active caspase-3 positive apoptotic cells were profoundly present in all three cerebellar layers.Reduced co-labeling of GLT-1 and GFAP revealed the altered glutamate transportation in cerebellum following diabetes.These results, exclusively derived from histology, immunohistochemistry and cellular quantification, provide first insight over the associative reciprocity between the glial activation, cellular degeneration and reduced glutamate transportation, which presumably lead to the behavioral alterations following STZ-induced diabetes.

View Article: PubMed Central - PubMed

Affiliation: School of Studies in Neuroscience, Jiwaji University Gwalior, India.

ABSTRACT
Behavioral impairments are the most empirical consequence of diabetes mellitus documented in both humans and animal models, but the underlying causes are still poorly understood. As the cerebellum plays a major role in coordination and execution of the motor functions, we investigated the possible involvement of glial activation, cellular degeneration and glutamate transportation in the cerebellum of rats, rendered diabetic by a single injection of streptozotocin (STZ; 45 mg/kg body weight; intraperitoneally). Motor function alterations were studied using Rotarod test (motor coordination) and grip strength (muscle activity) at 2nd, 4th, 6th, 8th, 10th, and 12th week post-diabetic confirmation. Scenario of glial (astroglia and microglia) activation, cell death and glutamate transportation was gaged using immunohistochemistry, histological study and image analysis. Cellular degeneration was clearly demarcated in the diabetic cerebellum. Glial cells were showing sequential and marked activation following diabetes in terms of both morphology and cell number. Bergmann glial cells were hypertrophied and distorted. Active caspase-3 positive apoptotic cells were profoundly present in all three cerebellar layers. Reduced co-labeling of GLT-1 and GFAP revealed the altered glutamate transportation in cerebellum following diabetes. These results, exclusively derived from histology, immunohistochemistry and cellular quantification, provide first insight over the associative reciprocity between the glial activation, cellular degeneration and reduced glutamate transportation, which presumably lead to the behavioral alterations following STZ-induced diabetes.

No MeSH data available.


Related in: MedlinePlus

Cell death detection in diabetic cerebellum. Active caspase-3 Immunolabeling revealed the conspicuous cell death following diabetes in cerebellum. Apoptotic cells were clearly visible in all the three layers of the diabetic cerebellum at all the time points (B–G). While in controls the labeling was negligible (A). The effect of diabetes was clearly demarcated in the Purkinje cell layer as Bergmann glial cells (B–G; red arrows) surrounding Purkinje cells (B–G; red arrowheads) were also showing intense immunolabeling of active caspase-3 in comparison to the molecular and granule cell layer of cerebellum. Insets were showing the enlarged images of apoptotic Purkinje cell with surrounded Bergmann glial cells. Scale bar = 50 μm. Cell quantitation (i) and area fraction (ii) graphs were presenting the increased stature of active caspase-3 immunolabeled apoptotic cells in various layers of the cerebellum following diabetes. Quantitative assessment data were showing significant increment in apoptotic cell population and volumetric fraction at all the diabetic time points in comparison to controls. Same alphabets on bars indicate non-significant differences between groups at the given time points (p ≤ 0.001). Value represents mean ± s.e.m. of the 30 readings/animal/time point. **p ≤ 0.001 for comparison of diabetic group with the respective controls.
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Figure 6: Cell death detection in diabetic cerebellum. Active caspase-3 Immunolabeling revealed the conspicuous cell death following diabetes in cerebellum. Apoptotic cells were clearly visible in all the three layers of the diabetic cerebellum at all the time points (B–G). While in controls the labeling was negligible (A). The effect of diabetes was clearly demarcated in the Purkinje cell layer as Bergmann glial cells (B–G; red arrows) surrounding Purkinje cells (B–G; red arrowheads) were also showing intense immunolabeling of active caspase-3 in comparison to the molecular and granule cell layer of cerebellum. Insets were showing the enlarged images of apoptotic Purkinje cell with surrounded Bergmann glial cells. Scale bar = 50 μm. Cell quantitation (i) and area fraction (ii) graphs were presenting the increased stature of active caspase-3 immunolabeled apoptotic cells in various layers of the cerebellum following diabetes. Quantitative assessment data were showing significant increment in apoptotic cell population and volumetric fraction at all the diabetic time points in comparison to controls. Same alphabets on bars indicate non-significant differences between groups at the given time points (p ≤ 0.001). Value represents mean ± s.e.m. of the 30 readings/animal/time point. **p ≤ 0.001 for comparison of diabetic group with the respective controls.

Mentions: A reflective cell death in cerebellum following STZ-induced diabetes upto 12 weeks was observed from active caspase-3 immunolabeling. Active caspase-3 positive cells were clearly evident in molecular layer, Purkinje cell layer and granule cell layer of the diabetic cerebellum in comparison to controls (Figure 6). Interestingly, active caspase-3 expression was more prominent in the nuclei of Purkinje cells and in surrounding Bergmann glial cell bodies in comparison to the molecular and granule cell layer. The inclination in Purkinje and Bergmann cell degeneration was constant at all the diabetic time points in comparison to controls. Quantitatively, caspase-3 positive cells were significantly increasing with advancing diabetic state, i.e., 2nd week [F(11,359) = 17.409, p ≤ 0.001], 4th week [F(11,359) = 22.529, p ≤ 0.001], 6th week [F(11,359) = 23.258, p ≤ 0.001], 8th week [F(11,359) = 22.187, p ≤ 0.001], 10th week [F(11,359) = 23.848, p ≤ 0.001], and 12th week [F(11,359) = 28.146, p ≤ 0.001] as compared to the respective controls (Figure 6i) suggesting a severe cellular degeneration in the cerebellar tissue. Percentage of area fraction of caspase-3 expression was also showing the similar trend. The increment of caspase-3 expression was consistent at all the diabetic time points, i.e., 2nd week [F(11,359) = 16.397, p ≤ 0.001], 4th week [F(11,359) = 22.076, p ≤ 0.001], 6th week [F(11,359) = 23.570, p ≤ 0.001], 8th week [F(11,359) = 22.544, p ≤ 0.001], 10th week [F(11,359) = 22.569, p ≤ 0.001], and 12th week [F(11,359) = 24.413, p ≤ 0.001] as compared to the controls (Figure 6ii).


Experimentally induced diabetes causes glial activation, glutamate toxicity and cellular damage leading to changes in motor function.

Nagayach A, Patro N, Patro I - Front Cell Neurosci (2014)

Cell death detection in diabetic cerebellum. Active caspase-3 Immunolabeling revealed the conspicuous cell death following diabetes in cerebellum. Apoptotic cells were clearly visible in all the three layers of the diabetic cerebellum at all the time points (B–G). While in controls the labeling was negligible (A). The effect of diabetes was clearly demarcated in the Purkinje cell layer as Bergmann glial cells (B–G; red arrows) surrounding Purkinje cells (B–G; red arrowheads) were also showing intense immunolabeling of active caspase-3 in comparison to the molecular and granule cell layer of cerebellum. Insets were showing the enlarged images of apoptotic Purkinje cell with surrounded Bergmann glial cells. Scale bar = 50 μm. Cell quantitation (i) and area fraction (ii) graphs were presenting the increased stature of active caspase-3 immunolabeled apoptotic cells in various layers of the cerebellum following diabetes. Quantitative assessment data were showing significant increment in apoptotic cell population and volumetric fraction at all the diabetic time points in comparison to controls. Same alphabets on bars indicate non-significant differences between groups at the given time points (p ≤ 0.001). Value represents mean ± s.e.m. of the 30 readings/animal/time point. **p ≤ 0.001 for comparison of diabetic group with the respective controls.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 6: Cell death detection in diabetic cerebellum. Active caspase-3 Immunolabeling revealed the conspicuous cell death following diabetes in cerebellum. Apoptotic cells were clearly visible in all the three layers of the diabetic cerebellum at all the time points (B–G). While in controls the labeling was negligible (A). The effect of diabetes was clearly demarcated in the Purkinje cell layer as Bergmann glial cells (B–G; red arrows) surrounding Purkinje cells (B–G; red arrowheads) were also showing intense immunolabeling of active caspase-3 in comparison to the molecular and granule cell layer of cerebellum. Insets were showing the enlarged images of apoptotic Purkinje cell with surrounded Bergmann glial cells. Scale bar = 50 μm. Cell quantitation (i) and area fraction (ii) graphs were presenting the increased stature of active caspase-3 immunolabeled apoptotic cells in various layers of the cerebellum following diabetes. Quantitative assessment data were showing significant increment in apoptotic cell population and volumetric fraction at all the diabetic time points in comparison to controls. Same alphabets on bars indicate non-significant differences between groups at the given time points (p ≤ 0.001). Value represents mean ± s.e.m. of the 30 readings/animal/time point. **p ≤ 0.001 for comparison of diabetic group with the respective controls.
Mentions: A reflective cell death in cerebellum following STZ-induced diabetes upto 12 weeks was observed from active caspase-3 immunolabeling. Active caspase-3 positive cells were clearly evident in molecular layer, Purkinje cell layer and granule cell layer of the diabetic cerebellum in comparison to controls (Figure 6). Interestingly, active caspase-3 expression was more prominent in the nuclei of Purkinje cells and in surrounding Bergmann glial cell bodies in comparison to the molecular and granule cell layer. The inclination in Purkinje and Bergmann cell degeneration was constant at all the diabetic time points in comparison to controls. Quantitatively, caspase-3 positive cells were significantly increasing with advancing diabetic state, i.e., 2nd week [F(11,359) = 17.409, p ≤ 0.001], 4th week [F(11,359) = 22.529, p ≤ 0.001], 6th week [F(11,359) = 23.258, p ≤ 0.001], 8th week [F(11,359) = 22.187, p ≤ 0.001], 10th week [F(11,359) = 23.848, p ≤ 0.001], and 12th week [F(11,359) = 28.146, p ≤ 0.001] as compared to the respective controls (Figure 6i) suggesting a severe cellular degeneration in the cerebellar tissue. Percentage of area fraction of caspase-3 expression was also showing the similar trend. The increment of caspase-3 expression was consistent at all the diabetic time points, i.e., 2nd week [F(11,359) = 16.397, p ≤ 0.001], 4th week [F(11,359) = 22.076, p ≤ 0.001], 6th week [F(11,359) = 23.570, p ≤ 0.001], 8th week [F(11,359) = 22.544, p ≤ 0.001], 10th week [F(11,359) = 22.569, p ≤ 0.001], and 12th week [F(11,359) = 24.413, p ≤ 0.001] as compared to the controls (Figure 6ii).

Bottom Line: Active caspase-3 positive apoptotic cells were profoundly present in all three cerebellar layers.Reduced co-labeling of GLT-1 and GFAP revealed the altered glutamate transportation in cerebellum following diabetes.These results, exclusively derived from histology, immunohistochemistry and cellular quantification, provide first insight over the associative reciprocity between the glial activation, cellular degeneration and reduced glutamate transportation, which presumably lead to the behavioral alterations following STZ-induced diabetes.

View Article: PubMed Central - PubMed

Affiliation: School of Studies in Neuroscience, Jiwaji University Gwalior, India.

ABSTRACT
Behavioral impairments are the most empirical consequence of diabetes mellitus documented in both humans and animal models, but the underlying causes are still poorly understood. As the cerebellum plays a major role in coordination and execution of the motor functions, we investigated the possible involvement of glial activation, cellular degeneration and glutamate transportation in the cerebellum of rats, rendered diabetic by a single injection of streptozotocin (STZ; 45 mg/kg body weight; intraperitoneally). Motor function alterations were studied using Rotarod test (motor coordination) and grip strength (muscle activity) at 2nd, 4th, 6th, 8th, 10th, and 12th week post-diabetic confirmation. Scenario of glial (astroglia and microglia) activation, cell death and glutamate transportation was gaged using immunohistochemistry, histological study and image analysis. Cellular degeneration was clearly demarcated in the diabetic cerebellum. Glial cells were showing sequential and marked activation following diabetes in terms of both morphology and cell number. Bergmann glial cells were hypertrophied and distorted. Active caspase-3 positive apoptotic cells were profoundly present in all three cerebellar layers. Reduced co-labeling of GLT-1 and GFAP revealed the altered glutamate transportation in cerebellum following diabetes. These results, exclusively derived from histology, immunohistochemistry and cellular quantification, provide first insight over the associative reciprocity between the glial activation, cellular degeneration and reduced glutamate transportation, which presumably lead to the behavioral alterations following STZ-induced diabetes.

No MeSH data available.


Related in: MedlinePlus