Oxidative stress suppression contributes to antiseizure action of axitinib and rapamycin in pentylenetetrazol-induced kindling

Abstract

Rapamycin and axitinib block different kinases in signaling pathways such as PI3K-Akt-mTOR and BDNF-TrkB, respectively. Both have antiseizure and antioxidative actions, which justify studying the combined effects of these drugs upon seizures and oxidative stress in the chronic model of epilepsy. The investigation aimed to look for the combined effect of rapamycin and axitinib upon pentylenetetrazol (PTZ)-kindled seizures and oxidative stress. Experiments were performed on 300 two-to four-month-old Wistar male rats, which had been kindled daily with PTZ (35.0 mg/kg, i.p.). Malondialdehyde (MDA) level, superoxide dismutase (SOD) activity, and glutathione (GSH) level were determined in brain tissues of kindled rats before and after the treatment. The analysis of antiseizure and antioxidative actions was performed using ED 50 of rapamycin and axitinib, with their combined administration using graded dosages of ED 50 of each drug. The median effective dose (ED 50 ) for rapamycin and axitinib was 0.93 and 4.97 mg/kg, respectively. ED 50 of rapamycin when combined with axitinib (2.0 mg/kg) was 0.60 mg/kg, which was reduced by 35.6% when compared with the ed 50 administered alone (P < 0.05). The MDA level increased from 152.9±24.8 to 388.3±49.2 nmol/mg of protein (P < 0.05), while SOD activity reduced from 11.14±2.33 to 3.54±1.08 IU/mg of protein (P < 0.05) in brain tissues of the kindled rats. Combined treatment with rapamycin (0.56 mg/kg, i.p.) and axitinib (2.0 mg/ kg, i.p.) resulted in a significant rise in SOD activity (11.09±1.86 IU/mg) and GSH level (7.32±1.34 µg/mg) when compared with the kindled rats (P < 0.05). Combined axitinib and rapamycin therapy have an antiepileptic and antioxidative effect on PTZ-kindled seizures.

Immunohistochemical neuroinflammatory markers in the hippocampus of PTZ-kindled rats under conditions of rapamycin and axitinib treatment

“…Earlier, we demonstrated that combined administration of rapamycin-blocker of mTOR and axitinib-blocker of tyrosine kinase B caused synergy antiseizure action [6]. Such a synergy developed in parallel with the pronounced antioxidant effects precipitation [6].…”

“…Based on the results of previous studies [6], the drugs with different mechanisms of action -mTOR inhibitor rapamycin and tyrosine-kinase B inhibitor axitinib were selected for the investigation of their antiseizure action upon immunohistochemical markers of PTZ-induced kindling seizures. Namely, such markers of chronic epilepsy as HIF-1α, TNF-α, and NF-kB levels in the dorsal hippocampus of fully kindled animals were measured following the earlier described method [17,18].…”

“…Namely, such markers of chronic epilepsy as HIF-1α, TNF-α, and NF-kB levels in the dorsal hippocampus of fully kindled animals were measured following the earlier described method [17,18]. Mentioned drugs possessed antiseizure activity and demonstrated synergy upon behavioural seizures [6].…”

“…Earlier, we demonstrated that combined administration of rapamycin-blocker of mTOR and axitinib-blocker of tyrosine kinase B caused synergy antiseizure action [6]. Such a synergy developed in parallel with the pronounced antioxidant effects precipitation [6]. Oxidative stress possesses a pathogenetic role in both brain epileptisation and neuroinflammation [7]; activating the brain antiepileptic system resulted in antioxidant effects [8,9].…”

“…PTZ-induced kindling as a model of chronic epileptic syndrome is characterized by the stable long-term heightening of brain excitability with comorbid behavioural deteriorations [14]. Primary epileptic foci start from limbic structures, and the hippocampus is regarded as a principal place for focal epileptogenesis, determining the development of seizures during PTZ administrations [6,8]. Neuroinflammation is among the principal mechanisms of PTZ-kindled seizure establishment [7,15,16].…”