Abstract
Purpose :
We have evidence that some exogenously administered hydrogen sulfide (H2S)-releasing compounds can attenuate excitatory amino acid neurotransmission in bovine isolated retina (Opere CA et al., JOPT, 34:10, 2018), suggesting a neuroprotective action for this gas in this tissue. The goal of this study was to investigate the neuroprotective effect of an H2S donor, diallyltetrasulfide (DATTS) against hydrogen peroxide (H2O2)-induced oxidative damage in bovine isolated retina.
Methods :
Freshly isolated bovine eyeballs were incubated in oxygenated Kreb’s buffer solution (37oC) for 1 h and then injected intravitreally with H2O2 and/or DATTS as follows: Group I: control (normal saline); Group II-III: hydrogen peroxide (H2O2; 10-5M; 10-4M); Group IV-XII: DATTS (10-7 M, 10-8 M, 10-9 M, 10-10 M) in the presence and absence of H2O2. After an hour of incubation, eyeballs were dissected, and retinas isolated and fixed in formalin. Fixed samples were stained with (H&E) for light microscopic study whereas non-stained sections were used for determination of apoptosis by TUNEL assay.
Results :
Treatment with H2O2 (10-5 M and 10-4 M) induced morphological changes in the ganglionic cell, inner plexiform, inner nuclear, outer nuclear and photoreceptor cell layers of the retina in a concentration-dependent manner. For instance, H2O2 (10-5 M and 10-4 M) induced a significant (n=3, p<0.001) loss in photoreceptor cells layer by 63% and 72%, respectively. Interestingly, the presence of DATTS partially attenuated the peroxide-induced loss in retinal integrity. In corroboration, TUNEL assay showed an average green fluorescence intensity that was significantly (n=3, p<0.001) higher (477±37% and 622±6.8%) for H2O2 (10-5 M and 10-4) than that of control group, respectively. Moreover, the presence of DATTS (10-10 M, 10-9 M, 10-8 M, 10-7 M) in H2O2 (10-4 M)-treated retinas significantly (n=3; p<0.001) attenuated the mean fluorescence intensity by 83±2.6%, 84±2.5%, 83±1.7%, 85±1.5%, respectively.
Conclusions :
We conclude that DATTS can protect retinal neurons from peroxide-induced oxidant stress, ex vivo.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.