Combination Antioxidant/NSAID Therapies and Oral/Topical Ocular Delivery Modes for Prevention of Oxygen-Induced Retinopathy in a Rat Model

Comparison of Glutathione Nanoparticles, CoEnzyme Q10, and Fish Oil for Prevention of Oxygen-Induced Retinopathy in Neonatal Rats

Notch ligands and receptors are important for cell specification and angiogenesis, but their role in oxygen-induced retinopathy (OIR) is not well studied. Delta-like ligand (DLL)-4/Notch inhibits angiogenesis, while Jagged-1/Notch promotes angiogenesis. We tested the hypothesis that early supplementation with antioxidants and/or fish oil curtails severe OIR by inducing DLL-4/Notch and reducing Jagged-1/Notch. Newborn rats were exposed to brief intermittent hypoxia (IH) during hyperoxia, during which they received daily oral supplements of (1) fish oil, (2) coenzyme Q10 (CoQ10) in olive oil (OO), (3) glutathione nanoparticles (nGSH), (4) fish oil + CoQ10, or (5) OO (controls) from birth (P0) to P14. At P14, the pups were placed in room air (RA) until P21, with no further treatment. Oxidative stress, apoptosis, ocular histopathology, and Notch signaling were assessed. Neonatal IH resulted in severe retinal damage consistent with retinopathy of prematurity (ROP). Retinal damage was associated with induced oxidative stress and Jagged-1/Notch signaling, as well as reduced DLL-4/Notch signaling. All treatments reversed these outcomes, but nGSH produced the most beneficial outcomes. Severe OIR promoted the induction of Jagged-1/Notch and curtailed DLL-4/Notch, which was an effect that could be reversed with nGSH supplementation. These findings may indicate a potential alternate pathway for ROP treatment and/or prevention.

Biomarkers of lung alveolarization and microvascular maturation in response to intermittent hypoxia and/or early antioxidant/fish oil supplementation in neonatal rats

OBJECTIVE

Extremely preterm infants experience frequent intermittent hypoxia (IH) episodes during oxygen therapy which causes significant damage to the lungs and curtails important signaling pathways that regulate normal lung alveolarization and microvascular maturation. We tested the hypothesis that early supplementation with fish oil and/or antioxidants in rats exposed to neonatal IH improves expression of lung biomarkers of alveolarization and microvascular maturation, and reduces IH-induced lung injury.

STUDY DESIGN/METHODS

From birth (P0) to P14, rat pups were exposed to room air (RA) or neonatal IH during which they received daily oral supplementation with either: (1) olive oil (OO) (control); (2) Coenzyme Q10 (CoQ10) in OO; (3) fish oil; (4) glutathione nanoparticles (nGSH); or (5) fish oil +CoQ10. At P14 pups were placed in RA until P21 with no further treatment. RA controls were similarly treated. Lung growth and alveolarization, histopathology, apoptosis, oxidative stress and biomarkers of alveolarization and microvascular maturation were determined.

RESULTS

Neonatal IH was associated with reduced lung weights and severe histopathological outcomes. These effects were curtailed with fish oil and nGSH. nGSH was also protective against apoptosis, while CoQ10 prevented IH-induced ROS production. Of all treatments, nGSH and CoQ10 + fish oil-induced vascular endothelial growth factor165 and CD31 (Platelet endothelial cell adhesion molecule-1), which are associated with angiogenesis. CoQ10 + fish oil improved alveolarization in RA and IH despite evidence of hemorrhage.

CONCLUSIONS

The benefits of nGSH and CoQ10 + fish oil suggest an antioxidant effect which may be required to curtail IH-induced lung injury. Further clinical assessment of the effectiveness of nGSH is warranted.

Antioxidants and/or fish oil reduce intermittent hypoxia-induced inflammation in the neonatal rat terminal ileum

Intermittent hypoxia (IH) is associated with the pathogenesis of necrotizing enterocolitis (NEC). We tested the hypothesis that early supplementation with antioxidants and/or fish oil protects the terminal ileum from oxidative injury induced by neonatal IH. Newborn rats were exposed to neonatal IH from birth (P0) until P14 during which they received daily fish oil, coenzyme Q10 (CoQ10), glutathione nanoparticles (nGSH), fish oil + CoQ10, or olive oil. Pups were then placed in room air from P14 to P21 with no further supplementation. Terminal ileum was assessed for IH-induced injury and inflammatory biomarkers. Neonatal IH induced severe damage consistent with NEC, and was associated with oxidative stress and elevations in PGE2, PGF2α, TxB2, NOS-2 and TLR-4, effects that were ameliorated with nGSH and combination CoQ10+fish oil. Early postnatal supplementation with antioxidants and/or fish oil during neonatal IH may be favorable for preserving gut integrity and reducing oxidative injury.

Comparison of coenzyme Q10 or fish oil for prevention of intermittent hypoxia-induced oxidative injury in neonatal rat lungs

BACKGROUND

Neonatal intermittent hypoxia (IH) results in oxidative distress in preterm infants with immature antioxidant systems, contributing to lung injury. Coenzyme Q10 (CoQ10) and fish oil protect against oxidative injury. We tested the hypothesis that CoQ10 is more effective than fish oil for prevention of IH-induced lung injury in neonatal rats.

METHODS

Newborn rats were exposed to two clinically relevant IH paradigms at birth (P0): (1) 50% O₂ with brief hypoxia (12% O₂); or (2) room air (RA) with brief hypoxia (12% O₂), until P14 during which they were supplemented with daily oral CoQ10, fish oil, or olive oil from P0 to P14. Pups were studied at P14 or placed in RA until P21 with no further treatment. Lungs were assessed for histopathology and morphometry; biomarkers of oxidative stress and lipid peroxidation; and antioxidants.

RESULTS

Of the two neonatal IH paradigms 21%/12% O₂ IH resulted in the most severe outcomes, evidenced by histopathology and morphometry. CoQ10 was effective for preserving lung architecture and reduction of IH-induced oxidative stress biomarkers. In contrast, fish oil resulted in significant adverse outcomes including oversimplified alveoli, hemorrhage, reduced secondary crest formation and thickened septae. This was associated with elevated oxidants and antioxidants activities.

CONCLUSIONS

Data suggest that higher FiO₂ may be needed between IH episodes to curtail the damaging effects of IH, and to provide the lungs with necessary respite. The negative outcomes with fish oil supplementation suggest oxidative stress-induced lipid peroxidation.

Involvement of TRPM2 Channel on Hypoxia-Induced Oxidative Injury, Inflammation, and Cell Death in Retinal Pigment Epithelial Cells: Modulator Action of Selenium Nanoparticles

Hypoxia (HYPX) in several eye diseases such as glaucoma and diabetic retinopathy causes oxidative cell death and inflammation. TRPM2 cation channel is activated by HYPX-induced ADP-ribose (ADPR) and oxidative stress. The protective role of selenium via inhibition of TRPM2 on the HYPX-induced oxidative cytotoxicity and inflammation values in the human kidney cell line was recently reported. However, the protective role of selenium nanoparticles (SeNP) on the values in the retinal pigment epithelial (ARPE-19) cells has not been clarified yet. In the current study, we investigated two subjects. First, we investigated the involvement of TRPM2 channel on the HYPX-induced oxidative injury, inflammation, and apoptosis in the ARPE-19 cells. Second, we investigated the protective role of SeNP via inhibition of TRPM2 channel on the HYPX-induced oxidative injury and apoptosis in the ARPE-19 cells. For the aims, the ARPE-19 cells were divided into four main groups as follows: Control (Ctr), SeNP (2.5 μg/ml for 24 h), HYPX (200 μM CoCl₂ for 24 h), and HYPX+SeNP. The TRPM2 current density and Ca²⁺ fluorescence intensity with an increase of mitochondrial membrane depolarization and oxygen free radical (OFR) generations were increased in the ARPE-19 cells by the treatment of HYPX. There was no increase of Ca²⁺ fluorescence intensity in the pre-treated cells with PARP-1 inhibitors (DPQ and PJ34) or in the presence of Ca²⁺-free extracellular buffer. When HYPX-induced TRPM2 activity was treated by SeNP and TRPM2 (2-APB and ACA) blockers, the increases of OFR generation, cytokine (TNF-α and IL-1β) levels, TRPM2, and PARP-1 expressions were restored. In conclusion, the exposure of HYPX caused mitochondrial oxidative cell cytotoxicity and cell death via TRPM2-mediated Ca²⁺ signaling and may provide an avenue for treating HYPX-induced retinal diseases associated with the excessive OFR and Ca²⁺ influx.