Protective Effects of Piceatannol against Selenite-Induced Cataract and Oxidative Damage in Rats

SMP30 Alleviates Oxidative Stress and Regulates Ca2+-ATPase Activity in UVR-B-Induced Cataracts in Rats

PURPOSE

Oxidative stress, ultraviolet radiation, and calcium imbalance are key components in the onset and advancement of cataract, which continue to be the leading cause of blindness globally. An important newly discovered aging maker, Senescence marker protein 30 (SMP30) regulates calcium and participates in mitigating oxidative stress damage. Here, we examined the beneficial role of SMP30 in protecting against ultraviolet radiation type B (UVR-B)-induced cataract in rats.

METHODS

Wistar rats (2 months) were arbitrarily assigned into 4 groups of 10 rats. These groups included the Control group, UVR-B group, adeno-associated virus 2 vectors negative control (AAV2-NC) group, and adeno-associated virus 2-mediated overexpression of SMP30 (AAV2-SMP30) group. The control group received Phosphate-buffered saline (PBS) via injection, while the AAV2-NC group and AAV-SMP30 group were separately injected with AAV2-NC and AAV2-SMP30 vectors. In addition to the control group, the remaining three experimental groups were subjected to ultraviolet light exposure 4 weeks post-injection. The lens opacity was examined by stereoscopic microscope, and the lenses were separated to measure oxidative damage parameters particularly superoxide dismutase (SOD), glutathione peroxidase (GPX), and Ca2+-ATPase activity. The localization and expression of SMP30 and Ca2+-ATPase in the lenses were determined using immunohistochemistry and RT-qPCR.

RESULTS

After UVR-B irradiation, the AAV2-SMP30 group exhibited a substantial decrease in lens opacity compared to the UVR-B group. The results revealed a notable downregulation of SMP30 expression and the activities of SOD, GPX, and Ca2+-ATPase of rat lens following exposure to UVR-B radiation. However, SMP30 overexpression partially reversed these effects. In vivo experiments demonstrated SMP30 overexpression attenuated the UVR-B-induced decline in SOD, GPX, and Ca2+-ATPase activities.

CONCLUSION

This study demonstrates that SMP30 has the potential to reduce lens opacity caused by UVR-B by increasing antioxidant stress and regulating Ca2+-ATPase activity. SMP30 might be a cutting-edge target for the treatment of cataracts.

Carbon Monoxide Releasing Molecule-3 Alleviates Oxidative Stress and Apoptosis in Selenite-Induced Cataract in Rats via Activating Nrf2/HO-1 Pathway

PURPOSE

This study investigated the protective effect of carbon monoxide releasing molecule-3 (CORM-3), the classical donor of carbon monoxide, on selenite-induced cataract in rats and explore its possible mechanism.

METHODS

Sprague-Dawley rat pups treated with sodium selenite (Na2SeO3) were chosen as the cataract model. Fifty rat pups were randomly divided into 5 groups: Control group, Na2SeO3 (3.46 mg/kg) group, low-dose CORM-3 (8 mg/kg/d) + Na2SeO3 group, high-dose CORM-3 (16 mg/kg/d) + Na2SeO3 group, and inactivated CORM-3 (iCORM-3) (8 mg/kg/d) + Na2SeO3 group. The protective effect of CORM-3 was tested by lens opacity scores, hematoxylin and eosin staining, TdT-mediated dUTP nick-end labeling assay, and enzyme-linked immunosorbent assay. Besides, quantitative real-time PCR and western blotting were used for mechanism validation.

RESULTS

Na2SeO3 induced nuclear cataract rapidly and stably, and the achievement ratio of Na2SeO3 group was 100%. CORM-3 alleviated lens opacity of selenite-induced cataract and attenuated the morphological changes of the rat lens. The levels of antioxidant enzymes GSH and SOD in rat lens were also increased by CORM-3 treatment. CORM-3 significantly reduced the ratio of apoptotic lens epithelial cells, besides, CORM-3 decreased the expression of Cleaved Caspase-3 and Bax induced by selenite and increased the expression of Bcl-2 in rat lens inhibited by selenite. Moreover, Nrf-2 and HO-1 were upregulated and Keap1 was downregulated after CORM-3 treatment. While iCORM-3 did not exert the same effect as CORM-3.

CONCLUSIONS

Exogenous CO released from CORM-3 alleviates oxidative stress and apoptosis in selenite-induced rat cataract via activating Nrf2/HO-1 pathway. CORM-3 may serve as a promising preventive and therapeutic strategy for cataract.