Related Experiment Video
Updated: Sep 17, 2025
Retinal Pathophysiological Evaluation in a Rat Model
Published on: May 6, 2022
Retinal Angiogenesis in Methamphetamine Self-Administration Rats
Minsup Lee1, Bo J Wood2,3, Hyeon Hak Jeong4
1Department of Molecular & Cellular Physiology, Louisiana State University Health Shreveport, Shreveport, Louisiana, United States.
Purpose:
Given the evidence of a link between methamphetamine (METH) exposure and retinal vascular abnormalities, this study aims to investigate the molecular and cellular mechanisms underlying METH-induced retinal angiogenesis using a unique self-administration rat model and primary rat retinal microvascular endothelial cells (RRMECs).
Method:
To model the impact of compulsive use of METH, rats underwent an 8-week METH long-access self-administration protocol, with retinal tissues analyzed using whole retinal flatmount imaging and vascular network quantification. Proteomic analysis via liquid chromatography/tandem mass spectrometry identified differentially expressed proteins, while RRMECs were treated with METH to assess molecular changes through immunoblotting and quantitative RT-PCR.
Results:
Consistent with compulsive use of METH in humans and our previous experience with this model, rats self-administered high levels of METH. METH self-administration elevated dopamine levels in the vitreous humor and increased vascular density in both superficial and deep capillary layers across central, mid-peripheral, and peripheral retina regions. Proteomic analysis revealed 148 differentially expressed retinal proteins, with gene ontology enrichment highlighting pathways related to abiotic stimuli, hypoxia, and ischemia. Increased hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor a (VEGFa) expression confirmed a hypoxia-driven angiogenesis process, further supported by in vitro experiments showing enhanced endothelial cell proliferation and HIF-1α/VEGFa expression. Additionally, TAAR-1 upregulation in both the retina and endothelial cells was observed, with TAAR-1 antagonism reducing METH-induced endothelial cell proliferation and modulating HIF-1α/VEGFa signaling.
Conclusions:
METH self-administration leads to significant retinal vascular changes and angiogenesis, driven by upregulation of hypoxia-related pathways. TAAR-1 plays a critical role in endothelial cell proliferation through the HIF-1α/VEGFa pathway, potentially contributing to pathological retinal conditions.
Insights
Methamphetamine (METH) use causes retinal vascular changes and new blood vessel growth (angiogenesis) by activating hypoxia pathways. Trace amine-associated receptor 1 (TAAR-1) is key in this METH-induced angiogenesis.
Area of Science:
- Ophthalmology
- Vascular Biology
- Neuroscience
Background:
- Methamphetamine (METH) exposure is linked to retinal vascular abnormalities.
- Understanding the molecular mechanisms of METH-induced retinal angiogenesis is crucial for preventing vision loss.
Purpose of the Study:
- To investigate the molecular and cellular mechanisms of METH-induced retinal angiogenesis.
- To utilize a rat self-administration model and primary rat retinal microvascular endothelial cells (RRMECs).
Main Methods:
- Rats underwent an 8-week METH long-access self-administration protocol.
- Retinal tissues were analyzed using flatmount imaging and vascular quantification.
- Proteomic analysis, immunoblotting, and quantitative RT-PCR assessed molecular changes in retinal tissues and RRMECs.
Main Results:
- METH self-administration increased retinal vascular density and dopamine levels.
- Proteomic analysis revealed 148 differentially expressed proteins, highlighting hypoxia and ischemia pathways.
- Increased hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor a (VEGFa) confirmed hypoxia-driven angiogenesis.
- Trace amine-associated receptor 1 (TAAR-1) upregulation was observed, and its antagonism reduced METH-induced proliferation and modulated HIF-1α/VEGFa signaling.
Conclusions:
- METH self-administration induces significant retinal vascular changes and angiogenesis via hypoxia-related pathways.
- TAAR-1 plays a critical role in METH-induced endothelial cell proliferation through the HIF-1α/VEGFa pathway.
- These findings suggest a mechanism for METH-related pathological retinal conditions.
