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Updated: Oct 1, 2026
Vibratome Sectioning Mouse Retina to Prepare Photoreceptor Cultures
Published on: December 22, 2014
Absence of photoreceptor rescue with D-cis-diltiazem in the rd mouse
Basil S Pawlyk1, Tiansen Li, Michael S Scimeca
1Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA.
Purpose:
Because of a previous report suggesting that D-cis-diltiazem slows retinal degeneration in rd mice, this study was undertaken to examine the effect of D-cis-diltiazem on photoreceptor structure and function in this line of mice.
Methods:
Mice were randomly assigned to daily intraperitoneal injections of D-cis-diltiazem or saline between postnatal days 9 and 24. On postnatal day 26 or 27, retinal function was assessed by recording dark-adapted bright-flash ERGs in all animals. Retinal morphology was examined in fixed sections and in immunolabeled frozen sections. Examiners were masked to the treatment group assignment.
Results:
On postnatal days 26 and 27, diltiazem- and saline-treated mice had only one row of remaining photoreceptor cells throughout most of the central retina. Cone cells in the periphery had remnants of inner segments. Total cell counts and separate counts of rod and cone photoreceptor cells by immunostaining were similar in the diltiazem- versus saline-treated mice. Both groups of mice had, on average, comparable subnormal ERG amplitudes.
Conclusions:
D-cis-Diltiazem had no detectable effect on preservation of photoreceptor structure and function in rd mice.
Insights
D-cis-diltiazem did not slow retinal degeneration in rd mice. This study found no significant differences in photoreceptor structure or function between treated and untreated mice, indicating no protective effect.
Area of Science:
- Ophthalmology
- Neuroscience
- Pharmacology
Background:
- Retinal degeneration is a significant cause of vision loss.
- Previous studies suggested D-cis-diltiazem might slow degeneration in rd mice.
- Understanding the mechanisms of retinal degeneration is crucial for developing treatments.
Purpose of the Study:
- To investigate the effect of D-cis-diltiazem on photoreceptor structure and function in rd mice.
- To validate or refute previous findings on D-cis-diltiazem's potential therapeutic effects.
- To assess the drug's impact on retinal integrity and visual electrophysiology.
Main Methods:
- Randomized assignment of rd mice to daily D-cis-diltiazem or saline injections.
- Assessment of retinal function using dark-adapted bright-flash electroretinograms (ERGs).
- Examination of retinal morphology through fixed and immunolabeled frozen sections.
Main Results:
- Both D-cis-diltiazem and saline groups showed significant photoreceptor loss by postnatal day 26/27.
- No significant differences in photoreceptor cell counts (rod and cone) were observed between groups.
- Electroretinogram (ERG) amplitudes were comparable and subnormal in both treated and control mice.
Conclusions:
- D-cis-diltiazem demonstrated no detectable effect on preserving photoreceptor structure in rd mice.
- The drug did not improve or maintain retinal function as measured by ERGs.
- These findings do not support the use of D-cis-diltiazem for treating retinal degeneration in this mouse model.
