Evaluation of the neuroprotective effect of carvacrol on total retina in a rabbit retinal degeneration modelEvaluation of the neuroprotective effect of carvacrol on total retina in a rabbit retinal degeneration model

INDA, AYELÉN; MARTINEZ, SOFIA M.; RIOS, MAXIMILIANO N.; GUIDO, MARIO; ALLEMANDI, DANIEL A.; RAVETTI, SOLEDAD; QUINTEROS, DANIELA A.

Rosario

Congreso; 7ma Reunión Internacional de Ciencias Farmacéuticas. RICiFa.; 2023

RICiFa

Neurodegenerative eye diseases cause progressive damage to the optic nerve and loss of retinal ganglion cells (RGCs), photoreceptors, and other nerve cells.Carvacrol (CAR), a natural monoterpene compound, has been shown to exhibit antioxidant and neuroprotective activities in the central nervous system. Therefore, in the present study, the neuroprotective and antiapoptotic activity of CAR in the retina was evaluated as a whole and specifically in retinal ganglion cells (RGCs). Through a model of retinal degeneration (MDR) in albino rabbits, caused by oxidizing and cytotoxic agents (L-buthionine sulfoximine - glutamate) through intravitreal administration, in an evaluation period of 9 days. For the evaluation of CAR, they were divided into 3 groups, healthy group (without MDR), control group (MDR+ Sc. propylene glycol: H20) and treated group (MDR+CAR).The application for the groups was a single dose of 40 μL intravitreally of the MDR, except for the healthy control. Subsequently, the control group was administered a single dose 40 μL of propylene glycol:H20 in a ratio (7:3) and the treated group was administered 40 μL of a CAR solution (0.065 mg/ml) intravitreally. Both solutions maintained optimal pH and osmolarity conditions for the ophthalmic route. Demonstrating not to be cytotoxic on retinal cells through histological sections.The viability of total neuronal cells from rabbit retina was performed by flow cytometry by measuring fluorescence intensity. Calcein was used as a fluorescent marker for live cells and propidide iodide was used for dead cells. Retinal cells without fluorescent markers were used as a negative control.Additionally, a pupillary contraction test was performed, prolonged stimulation with full-field blue light for 60 seconds, followed by a transition to the dark-adapted state that lasted another 60 seconds. Consequently, it is stimulated with white light (LUX: 350) for 30 seconds.The effect of CAR on RGCs was determined by the survival number of RGCs through histological sections and the percentage of apoptosis observed was by the TUNEL immunohistochemical procedure.Flow cytometry results indicated that CAR had a notable impact on reducing the dead cell population compared to the total number of cells evaluated in the MDR group. However, when it comes to the live cell population exposed to CAR, no statistically significant difference was observed compared to the MDR group. In pupillary contraction testing, CAR demonstrated the ability to maintain contraction percentages consistent with those observed in a healthy control group over the 30-second testing period. Furthermore, the CAR effect on pupillary contraction was statistically significant compared to the MDR group.CAR showed an increase in the number of survivals of CGR compared to MDR. Likewise, CAR decreased the apoptotic index by 20% compared to MRD, maintaining the survival percentage compared to the negative control.