Authors: Teodora Alexa, Andrei Dondaş, Cătălina Roxana Bohotin, Andrei Luca
Introduction: Cobalt chloride (CoCl2) is a widely used hypoxia-mimetic; acute cobalt administration has been reported to exert cytotoxic effects on several types of cells, probably by increasing reactive oxygen species and mitochondrial pathways. The aim of this study was to assess the effect of two different routes of CoCl2 administration - intraperitoneal (i.p.) and intrathecal (i.t.) - on experimental pain. Material and method: BALB/c male mice were divided into 4 groups: i.t. CoCl2 and i.t. saline - mice that received i.t. single-dose 0.025 mg/kg b.w. CoCl2 and equivalent volume of saline, respectively and groups i.p. CoCl2 and i.p. saline that received 25 mg/kg b.w. CoCl2 and equivalent volume of saline, respectively. Three hours after the CoCl2/saline administration, pain tests were performed (writhing and formalin-induced) in all groups. Results: Acute i.t. CoCl2 administration significantly decreased second-phase pain behavior when compared with i.t. saline in the paw formalin test. On orofacial formalin pain, both i.p. and i.t. CoCl2 administration induced a statistically significant decrease in both phases of the formalin test. No effect of either administration route was observed in the acetic-induced writhing test. Conclusions: Single-dose CoCl2 has a pronounced central effect on pain modulation, with anti-inflammatory-like consequences, probably due to its ability to block Calcium channels.
Keywords: Cobalt Chloride, intrathecal administration, animal model, inflammatory pain