Role of Lung P450 Oxidoreductase in Paraquat-Induced Collagen Deposition in the Lung

Multifaceted interplays between the essential players and lipid peroxidation in ferroptosis

Ferroptosis, a type of programmed cell death, represents a distinct paradigm in cell biology. It is characterized by the iron-dependent accumulation of reactive oxygen species, which induce lipid peroxidation (LPO), and is orchestrated by the interplay between iron, lipid peroxides, and glutathione. In this review, we emphasize the frequently overlooked role of iron in LPO beyond the classical iron-driven Fenton reaction in several crucial processes that regulate cellular iron homeostasis, including iron intake and export as well as ferritinophagy, and the emerging roles of endoplasmic reticulum-resident flavoprotein oxidoreductases, especially P450 oxidoreductases, in modulating LPO. We summarize how various types of fatty acids (FAs), including saturated, monounsaturated, and polyunsaturated FAs, differentially influence ferroptosis when incorporated into phospholipids. Furthermore, we highlight the therapeutic potential of targeting LPO to mitigate ferroptosis and discuss the regulatory mechanisms of endogenous lipophilic radical-trapping antioxidants that confer resistance to ferroptosis, shedding light on therapeutic avenues for ferroptosis-associated diseases.

Effect of Capparis spinosa Fruit Hydroalcoholic Extract on Paraquat-Induced Pulmonary Fibrosis in the Rat

Pulmonary fibrosis (PF) is a lethal inflammatory disease and there has been no effective medication for this progressive disease up to now. Paraquat is commonly used in agricultural settings to control weed growth and is one of the important risk factors for PF. Additionally, emerging evidence has demonstrated Capparis spinosa (C. spinose) fruit extract has anti-fibrotic, anti-inflammatory, and antioxidant properties. We aimed to evaluate whether C. spinose fruit hydroalcoholic extract has a positive effect against Paraquat-induced PF in rats. 30 male Wistar rats were randomly divided into 5 groups, which included: a control group, a Paraquat control group, a C. spinose group with a dose of 20 mg/kg, a C. spinose group with a dose of 30 mg/kg, a C. spinose group with a dose of 50 mg/kg. After 21 days of the treatment, levels of hydroxyproline and malondialdehyde (MDA) in lung tissue were assessed and lung indices and semi-quantitative histopathological changes were determined. The results showed that treatment with C. spinose, led to increased weight gain, whereas reduced lung weight. C. spinose demonstrated a decreasing effect on levels of MDA, and hydroxyproline in lung tissue. Moreover, histopathological data and the number of lung indices indicated the preventive role of C. spinose Paraquat-induced PF in rats.

Pathophysiological Changes in Rhesus Monkeys with Paraquat-Induced Pulmonary Fibrosis

Purpose

Pulmonary fibrosis is a life-threatening lung disorder. A comprehensive understanding of the pathophysiological changes in the development of pulmonary fibrosis will lead to new insights into its treatment.

Methods

We used a paraquat (PQ)-induced rhesus monkey model of pulmonary fibrosis to comprehensively investigate the process of pulmonary fibrosis development. Rhesus monkeys were orally administered PQ at concentrations of 25 mg/kg, 40 mg/kg, and 80 mg/kg. The dose was given once. Behavior and clinical data, such as PQ concentration, arterial oxygen saturation, biochemical evaluation, lung histopathology, and medical imaging, were continuously observed.

Results

Paraquat-exposed monkeys developed pulmonary fibrosis following an expected time course, especially at 25 mg/kg. CT images showed ground-glass lesions in the lung after 4 weeks, and pulmonary fibrosis persisted until the end of follow-up. Using pathological examination, the lung sustained collagen deposition and slight inflammatory cell infiltration. All rhesus monkeys had obvious inflammatory infiltration within 1 week according to the immunohistochemical results and the number of leukocytes in the blood. The CT results showed that pulmonary fibrosis had not formed, indicating that drugs with powerful anti-inflammatory ability are potential candidates for early pulmonary fibrosis treatment.

Conclusion

Our study describes the dynamic process of paraquat-induced pulmonary fibrosis in rhesus monkeys and provided a pathophysiological basis for the treatment of pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00408-022-00572-9.