Protective effect of U-74389G on paraquat induced pneumotoxicity in rats

Paraquat initially damages cochlear support cells leading to anoikis-like hair cell death

Paraquat (PQ), one of the most widely used herbicides, is extremely dangerous because it generates the highly toxic superoxide radical. When paraquat was applied to cochlear organotypic cultures, it not only damaged the outer hair cells (OHCs) and inner hair cells (IHCs), but also caused dislocation of the hair cell rows. We hypothesized that the dislocation arose from damage to the support cells (SCs) that anchors hair cells within the epithelium. To test this hypothesis, rat postnatal cochlear cultures were treated with PQ. Shortly after PQ treatment, the rows of OHCs separated from one another and migrated radially away from IHCs suggesting loss of cell-cell adhesion that hold the hair cells in proper alignment. Hair cells dislocation was associated with extensive loss of SCs in the organ of Corti, loss of tympanic border cells (TBCs) beneath the basilar membrane, the early appearance of superoxide staining and caspase-8 labeling in SCs below the OHCs and disintegration of E-cadherin and β-catenin in the organ of Corti. Damage to the TBCs and SCs occurred prior to loss of OHC or IHC loss suggesting a form of detachment-induced apoptosis referred to as anoikis.

Demographics, clinical characteristics and management of herbicide poisoning in tertiary care hospital

Herbicide poisoning is most common method of suicide in India and it is associated with high morbidity and mortality. Among different herbicidal poisonings the most predominantly found poisonings are paraquat and glyphosate. These compounds are highly toxic and their poisonings require proper management techniques. High fatality is seen in these cases which are mainly due to its inherent toxicity and lack of effective treatment. Common symptoms of these poisonings includes gastrointestinal corrosive effects with mouth and throat, epigastric pain and dysphagia, acid-base imbalance, pulmonary edema, shock and arrhythmia. Long term health effects include pulmonary fibrosis, renal failure, hepatic failure, heart failure, multi-organ failure or death. No proven antidote exists for these poisonings. So the treatment is mainly supportive. Initially gastric lavage or whole-gut irrigation using adsorbents such as Fuller's earth, bentonite or activated charcoal is recommended. In case of renal failure hemodialysis or hemoperfusion may be considered. However novel approaches like treatment with N-acetylcysteine, vitamin C, vitamin E, cyclophosphamide may also be helpful.

Atorvastatin attenuates the paraquat-induced pulmonary inflammation via PPARγ receptors: a new indication for atorvastatin

This study was carried out to highlight the role of PPARγ receptors and atorvastatin's protective effect on paraquat (PQ)-induced inflammation in the lungs. Forty-two male Wistar rats were exposed either against saline as control or PQ (3.5 mg/kg, IP) as test groups for 14 days. The test groups were nominated as: PQ, pioglitazone (PGT, 10 mg/kg, orally), atorvastatin (STN, 10 mg/kg, orally), PGT+STN, PGT+GW9662 (1 mg/kg) and STN+GW9662 (1 mg/kg). PGT and STN significantly (P<0.05) reduced the PQ-elevated myeloperoxidase activity, nitric oxide and malondialdehyde contents of the lungs and IL-6 and TNF-α concentrations in serum. Histopathological studies revealed alveolar edema and hemorrhages along with hyaline exudates in alveoli confirming that PGT and STN reduced the damages. Immunohistochemistry studies showed that the PQ-induced inflammation resulted in a severe recruitment of CD68(+) macrophages, which PGT and STN remarkably diminished them. STN regulated the PQ-up-regulated COX-2 expression. The antagonistic effect of GW9662 as an absolute antagonist of PPARγ receptors on anti-inflammatory effect of STN in the regulation of COX-2 expression was observed. These data provide a molecular proof(s) of the STN-produced protective effects on the PQ-induced pulmonary inflammation, which is antagonized by PPARγ antagonist indicating its anti-inflammatory effects via PPARγ receptors. Moreover, a new indication for atorvastatin is suggested.