Lymphocyte and its CD4+ and CD8+ subgroup changes after paraquat poisoning

Differences in epithelial-mesenchymal-transition in paraquat-induced pulmonary fibrosis in BALB/C and BALB/C (nu/nu) nude mice

Exposure to the toxic herbicide paraquat (PQ) can lead to the active absorption and enrichment of alveolar epithelial cells, resulting in pulmonary fibrosis and respiratory failure. At present, no effective clinical treatment is available. Notably, however, patients infected with human acquired immunodeficiency virus (HIV) (with T lymphocyte deficiency) do not show pulmonary fibrosis after PQ poisoning, suggesting that T lymphocytes may be involved in the occurrence and pathological development of lung fibers following PQ exposure, although relevant studies remain limited. Here, we found that the degree of pulmonary fibrosis induced by intragastric administration of PQ in congenital immunodeficiency BALB/C (nu/nu) nude (T lymphocyte loss) mice was lower than that in normal mice. However, pulmonary fibrosis was aggravated after transplantation of BALB/C (nu/nu) T lymphocytes into congenital immunodeficiency mice. This study is the first to report on the involvement of T lymphocytes in the occurrence and pathological development of lung fibers induced by PQ exposure. Thus, T cells may be an important cellular target for the clinical treatment of pulmonary fibrosis caused by PQ.

Effect of paraquat on cytotoxicity involved in oxidative stress and inflammatory reaction: A review of mechanisms and ecological implications

Paraquat (PQ) is a cheap and an effective herbicide, which is widely being used worldwide to remove weeds in cultivated crop fields. However, it can cause soil and water pollution, and pose serious harm to the environment and organisms. Several countries have started to limit or prohibit the use of PQ because of the increasing number of human deaths. Its toxicity can damage the organisms with a multi-target mechanism, which has not been fully understood yet. That is why it is hard to treat as well. The current research on PQ focuses on its targeted organ, the lungs, in which PQ mostly trigger pulmonary fibrosis. While there is a lack of systematic research, there are few studies published discussing its toxic effects at systematic level. This review summarizes the major damages caused by PQ in different organisms and partial mechanisms by which it causes these damages. For this purpose, we consulted several research articles that studied the toxicity of PQ in various tissues. We also listed some drugs that can be used to alleviate the toxicity of PQ. However, at present, the effectiveness of these drugs is still being explored in animal experiments and the study of their mechanism will also help in understanding the poisoning mechanism of PQ, which will ultimately lead to effective treatment in future.

Can kissing cause paraquat poisoning: A case report and review of literature

BACKGROUND

Paraquat is an effective, broad-spectrum, highly toxic quaternary ammonium herbicide. Paraquat poisoning has been reported frequently in recent years. It has severe lung, kidney, liver, and nervous system toxicity, and there is currently no specific antidote. Paraquat poisoning may follow ingestion, inhalation, and skin contact. There have been no previous reports of paraquat poisoning that resulted from kissing. This rare case provides a new reference for the prevention of paraquat poisoning.

CASE SUMMARY

A 27-year-old man came to the emergency department complaining that he had come into contact with paraquat by kissing his girlfriend, who had taken 80-120 mL 20% paraquat. After admission, his lung computed tomography (CT) showed increased lung markings. Redness and a burning sensation developed on his tongue, which progressed to painful erosions and coalescent ulcers. The final diagnosis was mild paraquat poisoning. Anti-inflammatory, antioxidant, and symptomatic treatment were initiated and continued for 7 d. Dyspnea did not occur, subsequent lung CT showed no significant changes, and the tongue pain was slightly improved. One month after discharge, the tongue injury was resolved.

CONCLUSION

This case indicated that the tongue and lung tissues are particularly vulnerable to paraquat toxicity, even after a limited exposure.

Depletion of NK cells attenuates paraquat-induced acute lung injury by manipulating macrophage polarization

Acute lung injury is the main causative factor in paraquat dichloride (PQ)-induced mortality. The innate immune system-triggered detrimental inflammatory cascade plays a vital role in PQ-induced acute lung injury. However, the role of natural killer (NK) cells, which are essential for innate response, in PQ-induced acute lung injury remains largely unknown. Here, we found that in an acute PQ poisoning model, depletion of NK cells attenuated PQ-induced lung injury by inhibiting macrophage polarization towards the M1 type. Specifically, the percentages of NK cells were reduced in the lung, spleen, and peripheral blood in a murine model of acute PQ poisoning. NK cells were aberrantly activated, evidenced by upregulation of the activating markers CD69, CD107a, and NKG2D and downregulation of the inhibitive marker KLRG1. Further, NK-specific depletion in mice greatly prolonged the survival time and ameliorated reactive oxygen species-induced damage following PQ treatment compared with the control group. Importantly, NK cell depletion alleviated macrophage and neutrophil infiltration in the lung and reversed PQ induced-macrophage polarization towards the pro-inflammatory M1 type. Our study demonstrates a crucial role of NK cells and NK cell-to-macrophage interaction in PQ-induced acute lung injury.