TY - JOUR
T1 - Sigma-1 receptor agonist, (+)-pentazocine, is neuroprotective in a Brown Norway rat microbead model of glaucoma
AU - Mysona, Barbara A.
AU - Zhao, Jing
AU - De Greef, Oceane
AU - Beisel, August
AU - Patel, Parth A.
AU - Berman, Lindsay
AU - Smith, Sylvia B.
AU - Bollinger, Kathryn
N1 - Funding Information:
This work was supported by the National Institutes of Health, National eye institute (NEI) grant number R01EY027406 and the NEI Center Core Grant (P30) for Vision research, P30EY031631. The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Funding Information:
This work was supported by the National Institutes of Health , National eye institute (NEI) grant number R01EY027406 and the NEI Center Core Grant (P30) for Vision research, P30EY031631 . The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2023/1
Y1 - 2023/1
N2 - Purpose: Glaucoma is a worldwide leading cause of irreversible blindness. Standard treatments lower intraocular pressure (IOP). Novel treatments to prevent optic nerve (ON) degeneration are needed. Here, we investigate the hypothesis that sigma-1 receptor (S1R) agonist (+)-pentazocine (PTZ) is neuroprotective in a Brown Norway (BN) rat, microbead model of glaucoma. Methods: BN rats (9–11 weeks, male and female) were treated by intraperitoneal injection, 3 times per week with (+)-PTZ (2 mg/kg) or vehicle (VEH) alone. Treatment started 1 week prior to intraocular injection of polystyrene microbeads to elevate IOP. IOP was measured 2–3 times per week. Five weeks post microbead injection, rats were euthanized. ONs were removed, then fixed and processed for 63x oil, light microscope imaging of toluidine blue stained ON cross sections. To facilitate comparison of ON morphology from VEH and (+)-PTZ treated rats with similar ocular hypertensive insults, rats were assigned to low (IOP ≤15.8 mmHg), moderate (15.8 < IOP <28.0 mmHg), and high (IOP ≥28.0 mmHg) groups based on average IOP in the microbead injected eye. Axon numbers, axon density, axonal and glial areas, axon loss, and axon size distributions of naïve, bead, and contralateral ONs were assessed using QuPath program for automated image analysis. Results: (+)-PTZ treatment of BN rats protected ONs from damage caused by moderate IOP elevation. Treatment with (+)-PTZ significantly reduced axon loss and glial areas, and increased axon density and axonal areas compared to ONs from VEH treated rats with moderate IOP. (+)-PTZ-mediated neuroprotection was independent of IOP lowering effects. At average IOP ≥28.0 mmHg, (+)-PTZ treatment did not provide measurable neuroprotection. ONs from contralateral eyes exhibited subtle, complex changes in response to conditions in the bead eyes. Conclusions: S1R agonist (+)-PTZ shows promise as a neuroprotective treatment for glaucoma. Future studies to understand the complex molecular mechanisms by which (+)-PTZ provides this neuroprotection are needed.
AB - Purpose: Glaucoma is a worldwide leading cause of irreversible blindness. Standard treatments lower intraocular pressure (IOP). Novel treatments to prevent optic nerve (ON) degeneration are needed. Here, we investigate the hypothesis that sigma-1 receptor (S1R) agonist (+)-pentazocine (PTZ) is neuroprotective in a Brown Norway (BN) rat, microbead model of glaucoma. Methods: BN rats (9–11 weeks, male and female) were treated by intraperitoneal injection, 3 times per week with (+)-PTZ (2 mg/kg) or vehicle (VEH) alone. Treatment started 1 week prior to intraocular injection of polystyrene microbeads to elevate IOP. IOP was measured 2–3 times per week. Five weeks post microbead injection, rats were euthanized. ONs were removed, then fixed and processed for 63x oil, light microscope imaging of toluidine blue stained ON cross sections. To facilitate comparison of ON morphology from VEH and (+)-PTZ treated rats with similar ocular hypertensive insults, rats were assigned to low (IOP ≤15.8 mmHg), moderate (15.8 < IOP <28.0 mmHg), and high (IOP ≥28.0 mmHg) groups based on average IOP in the microbead injected eye. Axon numbers, axon density, axonal and glial areas, axon loss, and axon size distributions of naïve, bead, and contralateral ONs were assessed using QuPath program for automated image analysis. Results: (+)-PTZ treatment of BN rats protected ONs from damage caused by moderate IOP elevation. Treatment with (+)-PTZ significantly reduced axon loss and glial areas, and increased axon density and axonal areas compared to ONs from VEH treated rats with moderate IOP. (+)-PTZ-mediated neuroprotection was independent of IOP lowering effects. At average IOP ≥28.0 mmHg, (+)-PTZ treatment did not provide measurable neuroprotection. ONs from contralateral eyes exhibited subtle, complex changes in response to conditions in the bead eyes. Conclusions: S1R agonist (+)-PTZ shows promise as a neuroprotective treatment for glaucoma. Future studies to understand the complex molecular mechanisms by which (+)-PTZ provides this neuroprotection are needed.
KW - Axon size distributions
KW - Axons
KW - Gliosis
KW - Neuroprotection
KW - QuPath
KW - Retinal ganglion cells
KW - Sigma-1 receptor
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U2 - 10.1016/j.exer.2022.109308
DO - 10.1016/j.exer.2022.109308
M3 - Article
C2 - 36400283
AN - SCOPUS:85142202359
SN - 0014-4835
VL - 226
JO - Experimental eye research
JF - Experimental eye research
M1 - 109308
ER -