Pro-regenerative effect of dipotassium glycyrrhizinate in the skeletal muscle after bothropic experimental envenoming

Abstract

The Viperidae in Brazil are responsible for most cases of snake envenoming, 87.5% of these events assigned to the genus Bothrops ("jararaca", "jararacuçu", "urutu-cruzeiro", "cotiara", "jararaca-do-rabo-branco", "malha-de-sapo", "patrona", "surucucurana", "combóia", "caiçara"). Such venoms as well as most of its toxins are predominantly myotoxic. The high incidence of these accidents associated with the ineffectiveness of antivenom to reverse local tissue damage becomes necessary to search for alternative therapies for the treatment of envenoming. The Glycyrrhizinate dipotassium (GD - C42H60K2016), derived of glycyrrhizic acid (GA - C42H62O16) has been widely used in pharmaceutical and cosmetic industry for its numerous functions, including antitumor action, antihistaminic, antibiotic and anti-inflammatory. During the process of myonecrosis molecular events, such as the expression of cytokines, are observed and corroborate to cellular changes. It is known that TNFa and IFNg operate in parallel in the early stages of envenoming (3 hours) and regeneration (3 days), this process being completed after 21 days. During regeneration activated satellite cells quickly begin to express MyoD. The generated myoblasts will differentiate and then merge to form new myofibers or multinuclear fused with final fragments of existing myofibers. The myogenin is crucial to the process of differentiation of myogenic cells in vivo and its effect in activating the expression of genes in skeletal muscle occurs after the transcriptional activity of MyoD. Considering the potential effects of GD on various tissues, the aim of this study is to evaluate, in vivo, the protective action of GD on gastrocnemius muscle morphology, and its possible contribution to the protein expression of MyoD, myogenin, IFNg and TNFa after bothropic experimental poisoning. For this, mice will be divided into 4 groups: group V (im injection of 100 mL of Bothrops jararacussu - 100 mg / mL), group GD (im injection of 100 mL of 2% GD - 100 mL, 1 , 4 mg / g animal weight), group V + GD (im injection of poison and GD 2%) and naïve group (N). The application of GD to the group V + GD occurs one hour after the venom inoculation. The animals will be sacrificed on the survival times of 3:24 h, 3, 7 and 21 days after injection, and the muscles will be used for electron microscopy, immunohistochemistry and western blotting. These techniques allow the characterization of histological regeneration after myonecrosis caused by the venom, and the pro-regenerative effect of GD in the gastrocnemius muscle. The findings of immunohistochemistry and western blotting allow the characterization of these cytokines and their involvement in muscle regeneration process, regulated / activated by proteins MyoD and myogenin. (AU)