Effect of Buah Merah (Pandanus conoideus Lamk.) Extract Supplementation on the Density and Apoptosis of Photoreceptor and Retinal Ganglion Cells in a Diabetic Rat Model

Diabetic retinopathy (DR) is a microvascular disorder of the retina due to diabetes mellitus (DM). Natural products are widely used to prevent and treat various diseases caused by DM. This study aims to evaluate the effect of <i>buah merah</i> (<i>Pandanus conoideus</i> Lamk.) extract on retinal density and apoptosis in a diabetic rat model. A total of 30 male rats (<i>Rattus norvegicus</i>) weighing 120-150 g were induced with diabetes using alloxan and divided into five groups: group 1 (normal control), 2 (diabetic control), 3 (diabetes + 1 mL <i>buah merah</i> extract), 4 (1.5 mL), and 5 (2 mL). <i>Buah merah</i> extract, equivalent to 12 mg total carotenoids, 10 mg total tocopherols, 1.348 mg alpha-tocopherol, and 3.4 mg beta-carotene, was administered for 14 days. Retina was examined using hematoxylin and eosin (HE) staining for photoreceptor and retinal ganglion cell density, and immunohistochemistry (IHC) of Caspase-3 for apoptosis. The results showed that group 3 had photoreceptor and retinal ganglion cell densities close to normal, with photoreceptor density values of 722.52 ± 147.56 and ganglion 18.73 ± 5.61. The post hoc test confirmed a significant protective effect of <i>buah merah</i> extract in group 3 (<i>p</i>-value 0.014). However, <i>buah merah</i> extract was found to maintain photoreceptor and retinal ganglion cell density, but no significant inhibitory effect was observed on photoreceptor or retinal ganglion cell apoptosis. Further studies are needed to better understand the mechanism and potential therapeutic effect of <i>buah merah</i> extract.