A partial agonist of PPARγ prevents paclitaxel-induced peripheral neuropathy in mice, by inhibiting neuroinflammation.

BACKGROUND AND PURPOSE: Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of paclitaxel, affecting 30-50% of patients. Increased survival and concern with patients' quality of life have encouraged the search for new tools to prevent paclitaxel-induced neuropathy. This study presents the glitazone 4-[(Z)-(2,4-dioxo-1,3-thiazolidin-5-ylidene)methyl]-N-phenylbenzene-sulfonamide (TZD-A1) as a partial agonist of peroxisome proliferator-activated receptor γ (PPARγ), its toxicological profile and effects on paclitaxel-induced CIPN in mice. EXPERIMENTAL APPROACH: Interactions of TZD-A1 with PPARγ were analysed using in silico docking and in vitro reporter gene assays. Pharmacokinetics and toxicity were evaluated using in silico, in vitro and in vivo (C57Bl/6 mice) analyses. Effects of TZD-A1 on CIPN were investigated in paclitaxel-injected mice. Axonal and dorsal root ganglion damage, mitochondrial complex activity and cytokine levels, brain-derived neurotrophic factor (BDNF), nuclear factor erythroid 2-related factor 2 (Nrf2) and PPARγ, were also measured. KEY RESULTS: Docking analysis predicted TZD-A1 interactions with PPARγ compatible with partial agonism, which were corroborated by in vitro reporter gene assays. Good oral bioavailability and safety profile of TZD-A1 were shown in silico, in vitro and in vivo. Paclitaxel-injected mice, concomitantly treated with TZD-A1 by i.p. or oral administration, exhibited decreased mechanical and thermal hypersensitivity, effects apparently mediated by inhibition of neuroinflammation and mitochondrial damage, through increasing Nrf2 and PPARγ levels, and up-regulating BDNF. CONCLUSION AND IMPLICATIONS: TZD-A1, a partial agonist of PPARγ, provided neuroprotection and reduced hypersensitivity induced by paclitaxel. Allied to its safety profile and good bioavailability, TZD-A1 is a promising drug candidate to prevent and treat CIPN in cancer patients.

Toxicological and anti-inflammatory profile of Synadenium grantii Hook. f. in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Synadenium grantii Hook. f., popularly known as "janaúba" or "leiterinha", is used in the folk medicine to treat gastric disorders, some types of neoplasias and inflammatory diseases. AIM OF THE STUDY: The aim of this study was to show the anti-inflammatory activity of the methanol extract obtained from S. grantii stems and also certify the safety of the extract performing toxicological analysis. MATERIAL AND METHODS: The anti-inflammatory activity was investigated using carrageenan-induced inflammation in the subcutaneous tissue of male Swiss mice orally pre-treated with the S. grantii extract (1, 3 or 10 mg/kg). The leukocyte influx (optical microscopy) and secretion of chemical mediators (TNF, IL-6 and IL-1ß, by enzyme-linked immunosorbent assay) were quantified in the inflamed exudate. The toxicity was investigated using the dose-fixed procedure (acute toxicity) and repeated dose 28-day (subacute toxicity) in mice orally treated with S. grantii extract. The open field and rota-rod test were used to evaluate possible interference of adverse effect of S. grantii on motor coordination, locomotor and exploratory activity. RESULTS: The analysis of the inflammatory exudate of S. grantii-treated mice demonstrated reduction in the polymorphonuclear cells (PMN) migration to the inflamed tissue, as well as the reduction of the pro-inflammatory cytokines TNF and IL-1ß. Furthermore, the acute and sub-acute toxicity studies did not show significant changes in body weight, general behaviour, biochemical parameters, organ weight and liver and kidney histopathological analysis. However, animals acutely treated with S. grantii presented reduction in the number of crosses in relation to the vehicle group, without significant difference in the number of elevations and latency time between the groups in rota-rod test. The obtained results allow to set the NOAEL (Non-observed-adverse-effect level) in 100 mg/kg for this specie of rodent. CONCLUSIONS: Together, the results herein obtained show that S. grantii extract presented anti-inflammatory activity by decreasing the influx of PMN to the inflamed tissue, as well as the cytokines TNF and IL-1ß levels. In addition, S. grantii extract seemed not to present significant acute or subacute toxicity when administered to mice, demonstrating for the first time the safety of this extract, when orally administered.