文獻快訊 | 巖藻黃質(zhì)對實驗性青光眼模型中視網(wǎng)膜神經(jīng)節(jié)細(xì)胞的保護作用及對 Parkin 介導(dǎo)的線粒體自噬的調(diào)控
發(fā)布時間：
2025-09-25
在實驗性青光眼模型的研究中，ICare Tonolab大小鼠眼壓計被證實是監(jiān)測大鼠眼壓（IOP）的高效且可靠的工具。
研究目的
青光眼是一種可導(dǎo)致不可逆失明的常見神經(jīng)退行性疾病。本研究旨在探究巖藻黃質(zhì)能否通過調(diào)控實驗性青光眼模型中 Parkin 介導(dǎo)的線粒體自噬，實現(xiàn)對視網(wǎng)膜神經(jīng)節(jié)細(xì)胞（RGCs）的保護作用。
研究方法
通過經(jīng)角膜緣激光光凝法，在 Sprague-Dawley（SD）大鼠體內(nèi)構(gòu)建實驗性青光眼模型；采用 Tonolab 大小鼠眼壓計(Icare Finland Oy) 監(jiān)測大鼠眼壓（IOP）；利用熒光金（FluoroGold）標(biāo)記法評估視網(wǎng)膜神經(jīng)節(jié)細(xì)胞的存活情況。在眼壓升高后第 3 天和第 2 周兩個時間點，采集大鼠視網(wǎng)膜與視神經(jīng)樣本，通過免疫組織化學(xué)技術(shù)及分子檢測方法，分析線粒體形態(tài)變化及相關(guān)基因 / 蛋白的表達水平。
研究結(jié)果
研究結(jié)果顯示，高眼壓大鼠體內(nèi)的線粒體自噬呈現(xiàn) “短期急性過度激活、長期功能受損” 的特征。玻璃體內(nèi)注射巖藻黃質(zhì)可提高視網(wǎng)膜神經(jīng)節(jié)細(xì)胞存活率、上調(diào) Bcl-2 蛋白表達，同時降低 Bax 與膠質(zhì)纖維酸性蛋白（GFAP）水平：在眼壓急性升高階段，巖藻黃質(zhì)可抑制 Parkin 蛋白表達及線粒體自噬體形成，從而減輕過度線粒體自噬；在眼壓長期升高狀態(tài)下，其可上調(diào)線粒體自噬相關(guān)蛋白表達、恢復(fù)線粒體自噬功能，進而促進受損線粒體的清除。
Figure 1. Effect of fucoxanthin on RGC survival in ocular hypertensive rat retinas. The retinal flat mounts of blank control rats (A, D and G), vehicle-treated ocular hypertensive rats (B, E and H) and fucoxanthin-treated ocular hypertensive rats (C, F and I). Quantitative analysis of RGC survival (J) (n=6; data are expressed as mean±SD; **p<0.01; scale bar=100 µm (A–I)). (K) Proposed mechanism by which fucoxanthin mitigates RGC loss in glaucomatous rats by modulating Parkin-mediated mitophagy (created by biorender.com). LAMP1, lysosomal-associated membrane protein 1; LC3, microtubule-associated protein 1A/1B-light chain 3; NC, normal control; OHT, ocular hypertension; OHT+FX, fucoxanthin-treated ocular hypertension; RGC, retinal ganglion cell.
Figure 2. Impact of fucoxanthin on apoptotic protein expression and Müller glial activation in glaucomatous rats. In untreated ocular hypertensive retinas, GFAP (B) and Bax (D) protein levels were elevated, while Bcl-2 (F) levels were reduced at both 3 days and 2 weeks post-IOP elevation. Fucoxanthin treatment resulted in a decrease in GFAP levels at both time points compared with vehicle-treated groups (B). Bax levels initially increased at 3 days but decreased at 2 weeks following fucoxanthin treatment (D), whereas Bcl-2 expression showed an increase at 14 days (F). At the mRNA level, ocular hypertensive retinas exhibited increased GFAP (C) and Bax (E) mRNA levels, with GFAP elevated at both 3 days and 2 weeks, and Bax increased at 2 weeks. Conversely, Bcl-2 (G) mRNA was decreased at both time points. Fucoxanthin treatment led to a reduction in GFAP mRNA at 3 days and 2 weeks, a decrease in Bax mRNA at 2 weeks and an increase in Bcl-2 mRNA at both 3 days and 2 weeks compared with the vehicle-treated group (n=3; data are expressed as mean±SD; *p<0.05; **p<0.01). BAX, Bcl-2 associated X protein; Bcl-2, B-cell lymphoma-2; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GFAP, glial fibrillar acidic protein;mRNA, messenger RNA; NC, normal control; OHT, ocular hypertension; OHT+FX, fucoxanthin-treated ocular hypertension.
Figure 3. Effect of fucoxanthin on mitophagy marker expression in glaucomatous rats. In untreated ocular hypertensive retinas, mRNA levels of Parkin (A), optineurin (B) and LAMP1 (D) increased at 3 days but decreased at 2 weeks, while LC3 (C) mRNA levels increased at both 3 days and 2 weeks. Following fucoxanthin treatment, mRNA levels of Parkin (A), optineurin (B), LC3 (C) and LAMP1 (D) decreased at 3 days but increased at 2 weeks compared with the vehicle-treated group (n=3; data are expressed as mean±SD; *p<0.05; **p<0.01). (E) Immunofluorescence analysis of Parkin and GFAP expression in vehicle-treated and fucoxanthin-treated ocular hypertensive retinas. Compared with vehicle-treated ocular hypertensive retinas (a–d), GFAP immunoreactivity decreased, whereas Parkin immunoreactivity increased, particularly in the retinal nerve fibre layer of fucoxanthin-treated ocular hypertensive retinas (e–h). Scale bar=50 µm. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GCL, ganglion cell layer; GFAP, glial fibrillar acidic protein; INL, inner nuclear layer; IPL, inner plexiform layer; LAMP1, lysosomal-associated membrane protein 1; LC3, microtubule-associated protein 1A/1B-light chain 3; mRNA, messenger RNA; NC, normal control; OHT, ocular hypertension; OHT+FX, fucoxanthin-treated ocular hypertension; ONL, outer nuclear layer; OPL, outer plexiform layer.
Figure 4. Effects of fucoxanthin on mitochondrial morphology and mitophagy. (A) Mitochondrial health was assessed using a scoring system based on the appearance of cristae in ultrastructural analyses. (B) NC group, where green arrows indicate healthy mitochondria. (C) OHT group, characterised by yellow arrows pointing to unhealthy mitochondria. (D) OHT+FX group, with red arrows indicating mitophagosomes. Relative to the control group (B), ocular hypertensive optic nerves (C) demonstrated a significant increase in the number of mitochondria (F), autophagosomes (G) and mitophagosomes (H) at both 3 days and 2 weeks post-treatment. Treatment with fucoxanthin resulted in a higher mitochondrial health score (E) and a greater number of mitochondria (F) at 3 days and 2 weeks compared with the vehicle-treated group. Notably, the number of autophagosomes (G) was reduced at 3 days but increased at 2 weeks in the fucoxanthin-treated group (n=3; data are expressed as mean±SD; *p<0.05; **p<0.01). Scale bar=500 nm (B–D). IOP, intraocular pressure; NC, normal control; OHT, ocular hypertension; OHT+FX, fucoxanthin-treated ocular hypertension.
Figure 5. Impact of fucoxanthin on mitophagy-related proteins in glaucomatous rats. Compared with the control group, the protein levels of Parkin (B) and LAMP1 (E) were significantly elevated at 3 days but decreased at 2 weeks. The protein levels of optineurin (C) and the ratio of LC3-II/LC3-I (D) were increased at both 3 days and 2 weeks in the ocular hypertensive optic nerves. In the fucoxanthin-treated group, the protein expression of Parkin (B), optineurin (C), LAMP1 (E) and the ratio of LC3-II/LC3-I (D) was notably reduced at 3 days and increased at 2 weeks compared with the vehicle-treated group (n=3; data are expressed as mean±SD; *p<0.05; **p<0.01). GAPDH, glyceraldehyde-3-phosphate dehydrogenase; LC3, microtubule-associated protein 1A/1B-light chain 3; LAMP1, lysosomal-associated membrane protein 1; NC, normal control; OHT, ocular hypertension; OHT+FX, fucoxanthin-treated ocular hypertension.
研究結(jié)論
巖藻黃質(zhì)可通過調(diào)控 Parkin 介導(dǎo)的線粒體自噬，在實驗性青光眼模型中發(fā)揮神經(jīng)保護作用。該研究表明，維持線粒體自噬穩(wěn)態(tài)有望成為青光眼治療的潛在靶點。
文獻來源： https://pubmed.ncbi.nlm.nih.gov/40841125