# Mingjing granule inhibits the subretinal fibrovascular membrane of two-stage laser-induced neovascular age-related macular degeneration in rats

## TL;DR

Mingjing granule combined with anti-VEGF treatment reduces fibrovascular lesions in a rat model of neovascular age-related macular degeneration.

## Contribution

The study demonstrates that Mingjing granule enhances anti-VEGF therapy by inhibiting fibrovascular membrane formation through anti-inflammatory and anti-fibrotic mechanisms.

## Key findings

- MG + anti-VEGF treatment significantly reduced fibrovascular lesion thickness and vascular leakage compared to anti-VEGF alone.
- MG + anti-VEGF inhibited inflammatory markers and fibrosis-related proteins more effectively than anti-VEGF alone.
- The combination treatment suppressed complement system activation and fibrotic protein expression.

## Abstract

The study aims to investigate the protective effect of Mingjing granule (MG) in a fibrovascular membrane rat model of neovascular age-related macular degeneration (nAMD) and explore the underlying mechanism.

The nAMD fibrovascular membrane model was established by two-stage laser photocoagulation. BN rats were randomly divided into four groups: the model group was gavaged with distilled water, the anti-VEGF group was given an intravitreous injection of ranibizumab, the MG + anti-VEGF group was gavaged with MG combined with an intravitreous injection of ranibizumab, and the normal group not modeled only fed conventionally. Lesions were evaluated by color fundus photograph, optical coherence tomography, fundus fluorescein angiography, and retinal pigment epithelial–choroid–sclera flat mount. The changes in the retinal structure were observed by histopathology. The expression of inflammatory cell markers F4/80, Iba-1, and glial fibrillary acidic protein (GFAP); the fibrosis-related factors collagen-1, fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor-beta (TGF-β); and the complement system-related factors C3a and C3aR in the retina were detected by immunofluorescence or qRT-PCR.

The current study revealed that MG + anti-VEGF administration more significantly reduced the thickness of fibrovascular lesions, suppressed vascular leakage (exudation area and mean density value), inhibited the area of fibrovascular lesions, and restrained the formation of the fibrovascular membrane than the anti-VEGF agent alone in the two-stage laser-induced rat model. The fluorescence intensities of F4/80, Iba-1, collagen-1, fibronectin, TGF-β, and C3aR showed more significant inhibition in MG + anti-VEGF-treated rats than the anti-VEGF agent alone. The mRNA expression levels of F4/80, Iba-1, GFAP, collagen-1, fibronectin, α-SMA, TGF-β, and C3a showed lower levels in rats treated with MG + anti-VEGF than the anti-VEGF agent alone.

Combining MG with anti-VEGF treatment inhibits the growth of the fibrovascular membrane more effectively than using anti-VEGF treatment alone. The mechanism underlying this effect may involve limiting inflammatory cell aggregation, controlling complement system activation, and decreasing the expression of the fibrotic protein.