Activation of Apoptosis in a βB1-CTGF Transgenic Mouse Model
Maximilian Weiss1, Sabrina Reinehr1, Ana M Mueller-Buehl1
1Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892 Bochum, Germany.
Abstract:
To reveal the pathomechanisms of glaucoma, a common cause of blindness, suitable animal models are needed. As previously shown, retinal ganglion cell and optic nerve degeneration occur in βB1-CTGF mice. Here, we aimed to determine possible apoptotic mechanisms and degeneration of different retinal cells. Hence, retinae were processed for immunohistology (n = 5-9/group) and quantitative real-time PCR analysis (n = 5-7/group) in 5- and 10-week-old βB1-CTGF and wildtype controls. We noted significantly more cleaved caspase 3+ cells in βB1-CTGF retinae at 5 (p = 0.005) and 10 weeks (p = 0.02), and a significant upregulation of Casp3 and Bax/Bcl2 mRNA levels (p < 0.05). Furthermore, more terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL+) cells were detected in transgenic mice at 5 (p = 0.03) and 10 weeks (p = 0.02). Neurofilament H staining (p = 0.01) as well as Nefh (p = 0.02) and Tubb3 (p = 0.009) mRNA levels were significantly decreased at 10 weeks. GABAergic synapse intensity was lower at 5 weeks, while no alterations were noted at 10 weeks. The glutamatergic synapse intensity was decreased at 5 (p = 0.007) and 10 weeks (p = 0.01). No changes were observed for bipolar cells, photoreceptors, and macroglia. We conclude that apoptotic processes and synapse loss precede neuronal death in this model. This slow progression rate makes the βB1-CTGF mice a suitable model to study primary open-angle glaucoma.
Insights
Apoptotic processes and synapse loss occur before neuronal death in βB1-CTGF mice, a new model for studying primary open-angle glaucoma.
Area of Science:
- Ophthalmology
- Neuroscience
- Cell Biology
Background:
- Glaucoma, a leading cause of blindness, requires effective animal models to understand its pathogenesis.
- Previous studies identified retinal ganglion cell and optic nerve degeneration in βB1-CTGF mice.
Purpose of the Study:
- To investigate apoptotic mechanisms and retinal cell degeneration in βB1-CTGF mice.
- To evaluate the suitability of βB1-CTGF mice as a model for primary open-angle glaucoma.
Main Methods:
- Immunohistology and quantitative real-time PCR were performed on retinae from 5- and 10-week-old βB1-CTGF and wildtype mice.
- Analysis included cleaved caspase 3, TUNEL staining, neurofilament H, and mRNA levels of Casp3, Bax/Bcl2, Nefh, and Tubb3.
- Synapse intensity (GABAergic and glutamatergic) and cell populations (bipolar, photoreceptors, macroglia) were assessed.
Main Results:
- βB1-CTGF mice showed increased cleaved caspase 3+ cells and elevated Casp3 and Bax/Bcl2 mRNA levels at 5 and 10 weeks.
- Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) positive cells were also increased in transgenic mice.
- Decreased neurofilament H, Nefh, and Tubb3 mRNA levels were observed at 10 weeks, along with reduced glutamatergic synapse intensity at both time points.
Conclusions:
- Apoptosis and synapse loss precede overt neuronal death in the βB1-CTGF mouse model.
- The slow progression rate suggests this model is suitable for studying primary open-angle glaucoma pathomechanisms.
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