Evaluation of neuroprotective activity of digoxin and semisynthetic derivatives against partial chemical ischemia

Abstract

Recently, cardiotonic steroids (CTS) have been shown to lead to the activation of Na,K‐ATPase at low concentrations in brain, promoting neuroprotection against ischemia. We report here the results of the use of digoxin and its semisynthetic derivatives BD‐14, BD‐15, and BD‐16 against partial chemical ischemic induction followed by reperfusion in murine neuroblastoma cells neuro‐2a (N2a). For chemical ischemic induction, sodium azide (5 mM) was used for 5 hours, and then reperfusion was induced for 24 hours. Na,K‐ATPase activity and protein levels were analyzed in membrane preparation of N2a cells pretreated with the compounds (150 nM), in the controls and in induced chemical ischemia. In the Na,K‐ATPase activity and protein levels assays, the steroids digoxin and BD‐15 demonstrated a capacity to modulate the activity of the enzyme directly, increasing its levels of expression and activity. Oxidative parameters, such as superoxide dismutase (SOD) activity, lipid peroxidation (thiobarbituric acid reactive substance), glutathione peroxidase (GPx), glutathione (GSH) levels, hydrogen peroxide content, and the amount of free radicals (reactive oxygen species) during induced chemical ischemia were also evaluated. Regarding the redox state, lipid peroxidation, hydrogen peroxide content, and GPx activity, we have observed an increase in the chemical ischemic group, and a reduction in the groups treated with CTS. SOD activity increased in all treated groups when compared to control and GSH levels decreased when treated with sodium azide and did not change with CTS treatments. Regarding the lipid profile, we saw a decrease in the content of phospholipids and cholesterol in the chemical ischemic group, and an increase in the groups treated with CTS. In conclusion, the compounds used in this study demonstrate promising results, since they appear to promote neuroprotection in cells exposed to chemical ischemia.

Effect of ouabain on calcium signaling in rodent brain: A systematic review of in vitro studies

“…Thus, in addition to expanding knowledge about signaling pathways and neuroprotective effects of low doses of ouabain and other cardiotonic, a strategy for the safe therapeutic use of cardiotonic steroids for neuroprotection would be the chemical modification of their structure to increase the therapeutic index of this class. Gamma-benzylidene digoxin derivatives are digoxin-derived molecules that have demonstrated low toxicity to cells ( de Oliveira et al, 2021 ) and have already demonstrated neuroprotection for chemical ischemia ( de Souza Gonçalves et al, 2019 ) and increased α3 activity and increased antioxidant defenses such as GSH, desired drug characteristics of neuroprotection ( Parreira et al, 2021 ).…”

Kolaviron neuroprotective effect against okadaic acid-provoked cognitive impairment

“…For this measurement [ 43 ], changes of absorption in the presence of 50 μl of supernatant and 250 μl of phosphate buffer solution (50 mM, pH 7.4) containing NaN₃ (1.25 mM), ethylenediaminetetraacetic acid (EDTA, 4 mM), H 2 O 2 (0.25 mM), GSH (1 mM), and nicotinamide adenine dinucleotide phosphate cofactor (NADPH, 0.16 mM) were read at 365 nm.…”

Cytotoxic effect of carbohydrate derivatives of digitoxigenin involves modulation of plasma membrane Ca2+‐ATPase

“…Many CGs have already been synthesized with changes in the lactone ring, in the steroidal nucleus and in the sugar moiety 4–7 . It has been reported that the number and positions of the hydroxyl groups present in the steroid nucleus affect the interaction with Na + /K + ‐ATPase 3 .…”

“…3 Many CGs have already been synthesized with changes in the lactone ring, in the steroidal nucleus and in the sugar moiety. [4][5][6][7] It has been reported that the number and positions of the hydroxyl groups present in the steroid nucleus affect the interaction with Na + /K + -ATPase. 3 Kanai et al, 8 raise the possibility of conferring α2 specificity by steroid core modifications that favor the formation of hydrogen bonds with Ser119 in α2.…”