Non-selective 5-HT · October 31, 2021

are founding scientists of FloNext Srl

are founding scientists of FloNext Srl. proalgesic response has not yet been investigated in animal models. Results Here, we reveal that a single systemic administration of thalidomide and its derivatives, lenalidomide and pomalidomide, elicits prolonged (~?35?days) mechanical and cold hypersensitivity in C57BL/6J mouse hind paw. Pharmacological antagonism or genetic deletion studies indicated that both TRPA1 and TRPV4, but not TRPV1, contribute to mechanical allodynia, whereas cold hypersensitivity was entirely due to TRPA1. Thalidomide per se did not stimulate recombinant and constitutive TRPA1 and TRPV4 channels in vitro, which, however, were activated by the oxidative stress byproduct, hydrogen peroxide. Systemic treatment with an antioxidant attenuated mechanical and cold hypersensitivity, and the increase in oxidative stress in hind paw, sciatic nerve, and lumbar spinal cord produced by thalidomide. Notably, central (intrathecal) or peripheral (intraplantar) treatments with channel antagonists or an antioxidant revealed that oxidative stress-dependent activation of peripheral TRPA1 mediates cold allodynia and part of mechanical allodynia. However, oxidative stress-induced activation of central TRPV4 mediated the residual TRPA1-resistant component of mechanical allodynia. Conclusions Targeting of peripheral TRPA1 and central TRPV4 may be required to attenuate pain associated with CIPN elicited by thalidomide and related drugs. mice developed mechanical and cold hypersensitivity with time courses similar to those observed in C57BL/6J mice, starting 3?h and lasting ~?35?days after thalidomide administration (Fig.?2a, b and Additional SVT-40776 (Tarafenacin) file 1: Fig. S1C). While and mice, thalidomide-evoked mechanical allodynia was significantly, but not completely, reduced (Fig.?2a, b). The relative contribution of TRPA1 and TRPV4 to thalidomide-evoked mechanical allodynia was further investigated Rabbit polyclonal to Caspase 3.This gene encodes a protein which is a member of the cysteine-aspartic acid protease (caspase) family.Sequential activation of caspases by evaluating the combined effect of channel pharmacological antagonism and genetic deletion. Thus, mechanical allodynia at day 7 after thalidomide injection was completely attenuated in was completely abolished in mice (Fig.?2e, f and Additional file 1: Fig. S1D). Similar results, for either mechanical or cold allodynia, were obtained if a lower dose of thalidomide (1?mg/kg) was tested in the three strains of mice (Additional file 1: Fig. S1E-G). Open in a separate window Fig. 2 Genetic deletion of TRPA1 and TRPV4 attenuates mechanical and cold hypersensitivity evoked by thalidomideand and mice and HC-030031 (HC03, 100?mg/kg, i.p.) or Veh in and mice and H2O2 (5 and 10?mM) in DRG neurons from mice in the presence of HC06 (10?M). Data are mean??SEM, and mice. The lower H2O2 concentration (500?M) elicited a Ca2+ response in neurons from mice, but not in those from mice (Fig.?3h). The residual calcium response to a higher concentration of H2O2 (10?mM) observed in DRG neurons from mice was abated in the presence of HC-067047 (Fig.?3h). Thus, in vitro data confirmed the ability of H2O2 to target the TRPV4 channel, provided that the concentration/dose of H2O2 is sufficiently high. Peripheral and central (spinal) TRPA1 and TRPV4 activation differentially contributes to thalidomide-induced mechanical allodynia One major issue raised by the present data is that, while oxidative stress inhibition completely attenuated mechanical allodynia, TRPA1 or TRPV4 pharmacological antagonism or gene deletion provided partial reduction, and total reduction was attained solely by the simultaneous inhibition of both channels. A recent study reported that oxidative stress generated at central or peripheral sites may contribute differently to cisplatin- and paclitaxel-evoked hypersensitivity [25]. Thus, we hypothesized whether oxidative stress activates SVT-40776 (Tarafenacin) TRPA1 and TRPV4 at different anatomical sites to mediate thalidomide-evoked mechanical allodynia. To test this hypothesis, we measured two oxidative stress biomarkers, H2O2 and the more stable peroxidation product of plasma membrane phospholipid peroxidation, 4-HNE [19]. H2O2 levels (Fig.?4a) SVT-40776 (Tarafenacin) and 4-HNE staining (Fig.?4b, c) were increased in homogenates or tissue slices, respectively, of the hind paw, sciatic nerve, and.