Vitamins A, C, and E Exert Anti-apoptotic Function in the Testis of Rats After Exposure to Zinc Oxide Nanoparticles

Abstract

Some reports emphasize that zinc oxide nanoparticles (ZnO NPs) are detrimental to the reproductive organs of animals. As such, this research aimed at exploring the apoptotic potential of ZnO NPs on testis along with the beneficial role of Vitamins (V) A, C, and E against ZnO NP-induced damage. To this aim, a population of 54 healthy, male Wistar rats were used in this work and then assigned into nine groups of 6 rats as G1: Control 1 (Water); G2: Control 2 (Olive oil); G3: VA (1000 IU/kg), G4: VC (200 mg/kg), G5: VE (100 IU/kg), G6: ZnO NPs exposed animals (200 mg/kg); and G7, 8 and 9: ZnO NPs-exposed animals that were pre-treated with either VA, C, or E. Apoptosis rates were estimated by measuring the level of apoptotic regulatory markers including Bcl-2-associated X (Bax) and B-cell lymphoma protein 2 (Bcl-2) using western blotting and qRT-PCR assays. The data indicated that ZnO NPs exposure elevates the level of Bax protein and gene expression, whereas the protein and gene expression of Bcl-2 was reduced. Further, the activation of caspase-3,7 occurred after exposure to ZnO NPs, while the above alterations were significantly alleviated in the rats that were co-treated with VA, C, or E and ZnO NPs relative to the rats in the ZnO NPs group. In summary, VA, C, and E exerted anti-apoptotic functions in the testis of rats following administration of ZnO NPs.

Keywords: Antioxidants; Apoptosis; Nanoparticles; Rats; Zinc Oxide.

FIG. 1. RT-qPCR analysis for apoptosis biomarkers. Gene expression of (A) Bcl-2-associated X (Bax), (B) B-cell lymphoma protein 2 (Bcl-2), and (C) Bax to Bcl-2 ratio. The results are reported as mean±SEM. ^*p<0.05 and ^***p<0.01 meaningfully different from the control group and ^#p<0.05, ^##p<0.01, and ^###p<0.001 show noticeable differences relative to the rats in ZnO NPs group. VE: vitamin E, VC: vitamin C, VA: vitamin A, ZnO: ZnO NPs.

FIG. 2. Western blotting analysis for apoptosis biomarkers. Protein expression of (B) Bcl-2-associated X (Bax), (C) B-cell lymphoma protein 2 (Bcl-2), and (D) Bax to Bcl-2 ratio (A). The data are reported as mean±SEM. ^**p<0.01 and ^***p<0.01 significantly different from the control group and ^###p<0.001 show noticeable differences relative to the rats in ZnO NPs group. VE: vitamin E, VC: vitamin C, VA: vitamin A, ZnO: ZnO NPs.

FIG. 3. Alterations of caspase 3,7 activity in experimental and control groups. Data are expressed as % relative to the control (100%) and reported as mean±SEM. ^***p<0.01 significantly different from control group and ^#p<0.05, ^##p<0.01 show noticeable differences relative to the rats that only received ZnO NPs (ZnO group). VE: vitamin E, VC: vitamin C, VA: vitamin A, ZnO: ZnO NPs.