Protective effects of Gac pulp from Momordica cochinchinensis fruit on optic nerve crush induced retinal degeneration

Abstract

Purpose : Momordica cochinchinesis (Gac) is known as a traditional medicinal fruit in eastern Asia including Vietnam. Gac contains high amount of carotenoids and vitamins. Therefore, Gac is used for health supplement purposes for eye diseases. On the other hand, the research about Gac and its eye protective effect has not been proven yet. The purpose of this study was to evaluate whether Gac pulp extract exhibit neuroprotective effects on optic nerve crush (ONC) mouse model.

Methods : Neuroprotective effect of Gac was evaluated using glutamate and BSO induced RGC5 cell death. Western blot analysis was performed on RGC5 cells to monitor the MAPK signaling pathway. AIF translocation was monitored by immunostaining. In mice, optic nerve crush (ONC) was performed on one side and a sham operation on the other. By gavage, animals were given 5 mg/kg and 50 mg/kg per day of Gac pulp extract, and Xalatan was used for positive control. Eight days after the ONC, the live cell number of RGCs was counted from the flat mount of eyes.

Results : In vitro assay, Gac showed neuroprotective effect in glutamate induced cell death. Western blot analysis showed that glutamate induced MAPK activation was block by Gac treatment. AIF translocation from mitochondria to nucleus was inhibited by Gac treatment. In animal model study, eight days after ONC treatment, the percentage of live retinal ganglion cells in vehicle-treated group was 44.9 ± 17.5%. 83.5 ± 5.8% of RGCs survived in animals receiving 50 mg/kg Gac daily. 80.4 ± 7.1% of RGCs survived in the treatment of Xalatan group.

Conclusions : In animal study, the data presented that Gac extract showed neuroprotective effects on RGCs after optic nerve crush. In vitro study, the mode of action study revealed that the neuroprotective effect of Gac may occur as the result of interference oxidative stress induced cell death.