Effects of hyperoxia exposure on the expression of Nrf2 and heme oxygenase-1 in lung tissues of premature rats

Chitosan/hesperidin nanoparticles formulation: a promising approach against ethanol-induced gastric ulcers via Sirt1/FOXO1/PGC-1α/HO-1 pathway

Hesperidin (Hes) protects different organs from damage by acting as a potent antioxidant and anti-inflammatory. This study aims to evaluate the gastroprotective effects of free hesperidin and its chitosan nanoparticles (HNPs) against ethanol-induced gastric ulcers in rats, hypothesizing that HNPs will enhance bioavailability and therapeutic efficacy due to improved solubility and targeted delivery. HNPs were synthesized via ion gelation and characterized using TEM, SEM, and zeta potential analyses. Key assessments included gastric acidity, histological analysis, and markers of inflammation, oxidative stress, and apoptosis. HNPs significantly decreased gastric acidity, reduced inflammatory and apoptotic markers, and enhanced antioxidant enzyme activities compared to free hesperidin and esomeprazole. Furthermore, Sirt-1, PGC-1α, HO-1, and FOXO1 gene expression were also evaluated. HNPs raised Sirt-1, PGC-1α, HO-1, and downregulated FOXO1, and they suppressed the activities of NF-κB p65, COX-2, IL-1β, CD86, FOXO1 P53, and caspase-3 and increased Sirt-1 activity. HNPs treatment notably restored antioxidant enzyme activity, reduced oxidative stress and inflammatory markers, and improved histological outcomes more effectively than free hesperidin and esomeprazole. These results indicate that chitosan nanoparticles significantly enhance the gastroprotective effects of hesperidin against ethanol-induced gastric ulcers, potentially offering a more effective therapeutic strategy. Further research should explore the clinical applications of HNPs in human subjects.

Ameliorative Effect of Chitosan/Spirulina platensis Ethanolic Extract Nanoformulation against Cyclophosphamide-Induced Ovarian Toxicity: Role of PPAR-γ/Nrf-2/HO-1 and NF-kB/TNF-α Signaling Pathways

Cyclophosphamide (CP) is an anticancer drug that causes infertility disorders. This study was designed to evaluate a nanoformulation of chitosan with an ethanolic extract from Spirulina platensis in terms of its protection against cyclophosphamide-induced ovarian toxicity. Nine groups of female Wistar rats were randomly assigned as follows: 1: control vehicle, 2: chitosan polymer, 3: telmisartan, 4: Spirulina platensis extract, 5: nanoformulation of the Spirulina platensis, and 6: single injection of CP; groups 7, 8, and 9 received the same treatments as those used in groups 3, 4, and 5, respectively, with a single dose of CP (200 mg/kg, I.P). The results displayed that the CP treatment decreased estradiol, progesterone, anti-mullerian hormone, and GSH content, and it downregulated PPAR-γ, Nrf-2, and HO-1 gene expression. In addition, the CP treatment caused an increase in the FSH, LH, and MDA levels. In the same manner, the protein expression of caspase-3, NF-kB, and TNF-α was upregulated in response to the CP treatment, while PPAR-γ was downregulated in comparison with the control. The rats treated with SPNPs exhibited a substantial reduction in the detrimental effects of oxidative stress and inflammation of the ovarian tissue. This study's conclusions showed that SPNPs counteracted the effects of CP, preventing the death of ovarian follicles and restoring the gonadotropin hormone balance and normal ovarian histological appearance.

Fenofibrate and Diosmetin in a rat model of testicular toxicity: New insight on their protective mechanism through PPAR-α/NRF-2/HO-1 signaling pathway

One of the most significant chemotherapeutic side effects of cisplatin (Cis) that limits its use and efficacy is testicular toxicity. Thus, the objective of the present study was to investigate the possible ameliorative effect of Fenofibrate (Fen), Diosmetin (D), and their combination against cis-mediated testicular damage. Fifty-four adult male albino rats were randomly allocated into nine groups (6 rats each): Control group, Fen (100 mg/kg), D20 (20 mg/kg), D40 (40 mg/kg), Cis group (7 mg/kg), Cis +Fen group (7 mg/kg+100 mg/kg), Cis+D20 group (7 mg/kg+20 mg/kg), Cis+D40 group (7 mg/kg+40 mg/kg), Cis+Fen+D40 treated group (7 mg/kg+100 mg/kg+40 mg/kg). Relative testicular weight, epididymal sperm count and viability, serum testosterone level, testicular oxidative stress indices, mRNA expression of peroxisome proliferator-activated receptor alpha (PPAR-α), nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1), histopathological, and immunohistochemical alterations were assessed. Our results revealed that cis administration induced testicular oxidative and inflammatory damage as indicated by a substantial reduction in relative testicular weight, sperm parameters, serum testosterone levels, the antioxidant enzyme activity of catalase, and Johnson's histopathological score, PPAR-α/NRF-2/HO-1 and proliferating cell nuclear antigen (PCNA) immunoexpression with marked increment in malondialdehyde (MDA), Cosentino's score, nuclear factor kappa B (NF-κβ p65), interleukin (IL)- 1β and caspase 3 in testicular tissue. Interestingly, Fen and D diminished the harmful effects of cis on testes via upregulation of the antioxidant activities and downregulation of lipid peroxidation, apoptosis, and inflammation. Moreover, the combination therapy Fen/D40 also exhibited a more pronounced enhancement of previous markers than either treatment alone. In conclusion, because of their antioxidant, anti-inflammatory, and anti-apoptotic properties, cotreatment with Fen or D or their combination could be beneficial in reducing the harmful impacts of cis on testicular tissue, particularly in patients that receive cis chemotherapy.

PAR2 Overexpression is Involved in the Occurrence of Hyperoxygen-Induced Bronchopulmonary Dysplasia in Rats

BACKGROUND

Bronchopulmonary dysplasia is a chronic lung disease commonly seen in preterm infants. It is characterized by delayed development of the alveoli and lung fibrosis. Protease-activated receptor 2 (PAR2) is an inflammatory driver that plays a proinflammatory role mainly through the P38 MAPK/NF-κB signaling pathway.

METHODS

Newborn rat pups were kept under air or oxygen at >60% concentration. Lung tissues were collected at postnatal days (P) 1, 4, 7, and 10 to observe pathological changes and take measurements.

RESULTS

In the hyperoxic group, P4 and P7 rats showed delayed alveolar development, septal thickening, and disturbances in alveolar structure.PAR2, P38 MAPK, NF-κB, and IL-18 expression at P4, P7, and P10 was significantly higher than in the air group.

CONCLUSION

PAR2 is involved in lung injury induced by persistent hyperoxia. Activated PAR2 promotes IL-18 overexpression through the P38 MAPK/NF-κB signaling pathway, which may be an important mechanism of PAR2-mediated lung injury in bronchopulmonary dysplasia.

Heme Oxygenase-1 as Therapeutic Target for Diabetic Foot Ulcers

A diabetic foot ulcer (DFU) is one of the major complications of diabetes. Wound healing under diabetic conditions is often impaired. This is in part due to the excessive oxidative stress, prolonged inflammation, immune cell dysfunction, delayed re-epithelialization, and decreased angiogenesis present at the wound site. As a result of these multifactorial impaired healing pathways, it has been difficult to develop effective therapeutic strategies for DFU. Heme oxygenase-1 (HO-1) is the rate-limiting enzyme in heme degradation generating carbon monoxide (CO), biliverdin (BV) which is converted into bilirubin (BR), and iron. HO-1 is a potent antioxidant. It can act as an anti-inflammatory, proliferative, angiogenic and cytoprotective enzyme. Due to its biological functions, HO-1 plays a very important role in wound healing, in part mediated through the biologically active end products generated by its enzymatic activity, particularly CO, BV, and BR. Therapeutic strategies involving the activation of HO-1, or the topical application of its biologically active end products are important in diabetic wound healing. Therefore, HO-1 is an attractive therapeutic target for DFU treatment. This review will provide an overview and discussion of the importance of HO-1 as a therapeutic target for diabetic wound healing.

The Nrf2 inhibitor brusatol has a protective role in a rat model of oxygen-induced retinopathy of prematurity

Nuclear factor-erythroid 2-related factor 2 (Nrf2) has been testified to be involved in the development of retinopathy of prematurity (ROP), which can cause childhood visual impairment. Whether brusatol, an Nrf2 inhibitor, could be utilized to treat ROP was unknown. The oxygen-induced retinopathy rat model was established to mimic ROP, which was further intravitreal administrated with brusatol. Vessel morphology and microglial activation in the retina were assessed with histology analysis. The relative expression levels of angiogenesis and inflammation-related molecules were detected with Western blot and real-time polymerase chain reaction methods. Intravitreal brusatol administration could alleviate both angiogenesis and microgliosis induced by hyperoxia, along with down-regulation of vascular endothelial growth factor, vascular endothelial growth factor receptor (VEGFR)-1, VEGFR-2, cluster of differentiation molecule 11B, tumor necrosis factor alpha, inducible nitric oxide synthase, glial fibrillary acidic protein, and IBA-1 expression. It was further revealed that Nrf2 and heme oxygenease-1 were diminished by brusatol administration. The results demonstrate the potential of intravitreal brusatol deliver to treat ROP with down-regulation of angiogenesis and microgliosis.

SIRT1-Related Signaling Pathways and Their Association With Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic and debilitating disease that can exert serious and overwhelming effects on the physical and mental health of premature infants, predominantly due to intractable short- and long-term complications. Oxidative stress is one of the most predominant causes of BPD. Hyperoxia activates a cascade of hazardous events, including mitochondrial dysfunction, uncontrolled inflammation, reduced autophagy, increased apoptosis, and the induction of fibrosis. These events may involve, to varying degrees, alterations in SIRT1 and its associated targets. In the present review, we describe SIRT1-related signaling pathways and their association with BPD. Our intention is to provide new insights into the molecular mechanisms that regulate BPD and identify potential therapeutic targets for this debilitating condition.