Molecular mechanism of compound anisodine in improving ischemic ophthalmopathy by regulating AMPK/mTOR pathway

This work aimed to explore the molecular mechanism by which Compound anisodine (CA) improved ischemic ophthalmopathy (IOP) in rats through regulation of the AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) pathway. Sixty Sprague Dawley rats were assigned into a blank control (BC) group (no treatment), an IOP group (IOP model established), normal saline (NS) group (additional injection sodium chloride based on IOP group), CA group (additional CA injection based on IOP group), CA + AMPKi group (additional AMPK inhibitor Compound C based on CA group), and CA + AMPKa group (additional AMPK activator Acadesine based CA group). Changes in retinal structure and function were assessed using iris imaging by scanning electron microscopy (SEM), retinal examination, blood oxygenation monitoring (BOM) parameters (ocular blood oxygen saturation (BOS) and perfusion index (PI)) in the eyes. Retinal tissues were acquired for hematoxylin-eosin (H&E) staining to observe pathological structural changes, and western blotting was carried out to detect AMPK and mTOR protein expressions. Relative to BC group, IOP and NS groups showed reduced iris vascular area and pericyte count, decreased rod cell response, maximum mixed response, and oscillatory potentials (OPs), lowered ocular blood oxygen saturation (BOS) and perfusion index (PI), and reduced retinal, inner nuclear layer (INL), and outer nuclear layer (ONL) thicknesses. Additionally, it was observed that retinal LC3 II/I and p-mTOR expressions were downregulated, while p-AMPK expression was upregulated ( P < 0.05). In contrast to the IOP group, the CA group exhibited substantial improvement in all the above indicators ( P < 0.05). In addition, the therapeutic effects of CA were reversed in the CA + AMPKi group, while the therapeutic outcomes of CA were further enhanced in the CA + AMPKa group. CA could mediate the AMPK/mTOR pathway to improve retinal damage in rats with IOP, providing a new molecular basis for preventing and treating IOP.