Effect of BDNF-TrKB pathway on apoptosis of retinal ganglion cells in glaucomatous animal model

Y. Liang, Y.-H. Yu, H.-J. Yu, L.-S. Ma

Department of Ophthalmology, the Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China. shanglu80619069@163.com

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• Ophthalmology

OBJECTIVE: The aim of this paper is to investigate the effect of BDNF-TrKB pathway on AOH by accessing its regulatory role in retinal ganglion cell apoptosis.
MATERIALS AND METHODS: Acute ocular hypertension (AOH) model in rats was established by anterior chamber perfusion to increase intraocular tension. Rats were randomly divided into AOH group, control group and k252a group, with ten rats in each group. Rats were sacrificed 72 h after animal procedures and eyeballs were harvested. HE staining was used to observe retinal structural changes at different time points. Immunohistochemical staining was used to observe the BDNF-positive cells in retinal tissues. TUNEL staining was conducted to measure apoptosis of retinal ganglion cells. Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) and Western blot were performed to detect mRNA and protein levels of BDNF, TrKB, PI3K and ERK1 in retinal tissues, respectively.
RESULTS: HE and TUNEL staining showed significant pathological changes and abundant apoptotic cells in rat retina of AOH group and k252a group compared with those of the control group (p<0.05). The number of survived retinal ganglion cells in the AOH group was lower than that of the control group (p<0.05). K252a group had the lowest number of survived retinal ganglion cells. Immunohistochemical results showed that BDNF was rarely expressed in rat retinal tissues of the control group, which was remarkably pronounced in the AOH group and k252a group. The number of BDNF-positive cells in the k252a group was higher than that in the AOH group (p<0.05). RT-PCR and Western blot indicated that mRNA and protein levels of relative genes in BDNF-TrKB and PI3K/ERK1 pathways were upregulated in AOH group (p<0.05), but were significantly downregulated in k252a group (p<0.05).
CONCLUSIONS: BNDF-TrKB pathway exerts a protective effect on retina against acute ocular hypertension by reducing retinal cell apoptosis.

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