Does trimetazidine exert cytoprotective activity on astrocytes subjected to hypoxia in vitro?

Neuroprotective potential of trimetazidine against tramadol-induced neurotoxicity: role of PI3K/Akt/mTOR signaling pathways

Tramadol (TRA) causes neurotoxicity whereas trimetazidine (TMZ) is neuroprotective. The potential involvement of the PI3K/Akt/mTOR signaling pathway in the neuroprotection of TMZ against TRA-induced neurotoxicity was evaluated. Seventy male Wistar rats were divided into groups. Groups 1 and 2 received saline or TRA (50 mg/kg). Groups 3, 4, and 5 received TRA (50 mg/kg) and TMZ (40, 80, or 160 mg/kg) for 14 days. Group 6 received TMZ (160 mg/kg). Hippocampal neurodegenerative, mitochondrial quadruple complex enzymes, phosphatidylinositol-3-kinases (PI3Ks)/protein kinase B levels, oxidative stress, inflammatory, apoptosis, autophagy, and histopathology were evaluated. TMZ decreased anxiety and depressive-like behavior induced by TRA. TMZ in tramadol-treated animals inhibited lipid peroxidation, GSSG, TNF-α, and IL-1β while increasing GSH, SOD, GPx, GR, and mitochondrial quadruple complex enzymes in the hippocampus. TRA inhibited Glial fibrillary acidic protein expression and increased pyruvate dehydrogenase levels. TMZ reduced these changes. TRA decreased the level of JNK and increased Beclin-1 and Bax. TMZ decreased phosphorylated Bcl-2 while increasing the unphosphorylated form in tramadol-treated rats. TMZ activated phosphorylated PI3Ks, Akt, and mTOR proteins. TMZ inhibited tramadol-induced neurotoxicity by modulating the PI3K/Akt/mTOR signaling pathways and its downstream inflammatory, apoptosis, and autophagy-related cascades.

Pharmacological screening of substances with cardioprotective effect in the group of 3-oxypyridine derivatives

Introduction: The search for new compounds with antihypoxic and cardioprotective effects among 3-oxypyridine derivatives is promising.

Research objectives: To study the anti-hypoxic and cardioprotective effects of 3-oxypyridine derivatives.

Materials and methods: The search for compounds with an antihypoxic effect was carried out on blood leukocytes of rats in in vitro. To simulate hypoxia, Oil for Tissue Culture (SAGE) was used, 500 µl of which was applied into wells over a growth medium in order to block gas exchange. The cardioprotective effect of 3-oxypyridine derivatives was studied in the model of coronary-occlusive myocardial infarction (30 minutes of ischemia, 90 minutes of reperfusion). The level of troponin I (Tn I) was determined as a biochemical marker of myocardial damage.

Results and discussion: In the in vitro experiments, when culting white blood cells, the lead compound in the group of 3-oxypyridine derivatives was identified under code LKhT 21–16, which increases the number of viable cells in the presence of hypoxia, surpassing the reference drugs. When confirming the chemical structure of the lead compound, LHT 21–16, a high sensitivity of the NMR spectroscopy method was revealed.

In studying the cardioprotective activity in the model of coronary-occlusive myocardial infarction compound LHT 21–16 exerted a marked cardioprotective effect when reducing the size of the necrotic zone and the level of biochemical marker Tn I.

Conclusions: 3-oxypiridine derivatives have antihypoxic and cardioprotective effects, which shows in a high number of surviving cells in the presence of hypoxia in the in vitro model, a reduced size of the necrotic zone and a reduced level of Tn I in the coronary-occlusive myocardial infarction.

Trimetazidine has protective effects on spermatogenesis in a streptozotocin-induced diabetic rat model

The aim of this study was to investigate the protective effects of trimetazidine (TMZ), as an antioxidant agent, on streptozotocin (STZ)-induced diabetic rats. A total of 50 male Sprague Dawley rats were randomly classified into five groups as follows: Group 1 (control), Group 2 (STZ-induced diabetic rats), Group 3 (STZ-induced diabetic rats treated orally with 1 cc/day isotonic saline), Group 4 (diabetic rats treated orally with 10 mg/kg/day TMZ) and Group 5 (diabetic rats treated orally with 20 mg/kg/day TMZ). After 8 weeks, orchiectomy was carried out. Histopathological and electron microscopic examinations were performed in all groups. In groups 1 and 5, the structural and ultra-structural findings of the testicular tissue and spermatogenesis were found normal. In groups 2, 3 and 4, similar results were obtained in terms of the impaired testicular architecture and degeneration of spermatogenesis. The administration of an optimal dose of TMZ protects against the harmful effects of diabetes mellitus on spermatogenesis in rats. TMZ therapy can be used to maintain normal spermatogenesis in diabetic rats.

Effect of trimetazidine on xanthine oxidoreductase expression in rat kidney with ischemia--reperfusion injury

Ischemia/reperfusion (I/R) injury is often responsible for delayed graft function after transplantation. Trimetazidine (TMZ) is an anti-ischemic and antioxidant agent used to protect grafts from I/R injury. With the supply of molecular oxygen upon reperfusion of ischemic tissues, xanthine oxidoreductase (XOR) metabolizes xanthine and hypoxanthine to uric acid and free radicals are generated. The aim of the study was to examine the effect of TMZ on XOR expression in rat kidney with I/R injury. The study was carried out on Wistar rats divided into two groups: animals treated with TMZ and control group receiving placebo. TMZ (10 mg/kg/day) was administered for 30 days. There were no significant differences in XOR expression in kidneys without ischemia between rats treated with TMZ and control group, whereas the XOR expression in kidneys with ischemia was significantly decreased in rats treated with TMZ as compared with control animals. The XOR expression in ischemic kidney was significantly lower in comparison with kidney without ischemia in the group treated with TMZ. We suggest that the decrease in xanthine oxidoreductase expression is one of the beneficial mechanisms of TMZ on I/R injury, preventing the degradation of purine nucleotides during the oxidation of hypoxanthine to xanthine and uric acid and formation of free radicals.

Erk1/2 and Akt kinases are involved in the protective effect of aniracetam in astrocytes subjected to simulated ischemia in vitro

The present study focused on the mechanism of cytoprotective effect of aniracetam on the primary rat astrocyte cultures exposed to simulated ischemia conditions in vitro. To study these mechanisms, the aniracetam-mediated modulation of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3-K)/Akt kinase pathways was determined. Simulated in vitro ischemia caused death of approximately 35% of astrocytes via apoptosis and decreased cell viability about 50% at 8 h. Exposure to aniracetam at concentrations of 0.1-10 microM in these conditions significantly decreased the number of apoptotic cells. Moreover, the intensification of 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyltetrazolinum bromide (MTT) conversion and the decrease of lactate dehydrogenase (LDH) release after 1 and 10 microM aniracetam treatment were observed indicating a significant increase in cell viability. When cultured astrocytes were incubated during 8 h simulated ischemia with [1,4-diamino-2,3-dicyano-1,4-bis(2-aminophenylthio)butadiene] (U0126), an extracellular regulated kinase 1 and 2 (Erk1/2) inhibitor or wortmannin, a phosphatidylinositol 3-kinase (PI3 kinase)/Akt inhibitor, the cell apoptosis was accelerated. These effects of used kinase inhibitors (both U0126 and wortmannin) were antagonized by adding 1 and 10 microM aniracetam to the culture medium. In addition, aniracetam significantly stimulated of phospho-Erk1/2 kinase and phospho-Akt expression. Maximum levels of Erk1/2 and Akt activation were observed as a result of treatment with 10 microM aniracetam. U0126 and wortmannin markedly attenuated the effects of aniracetam on expression of activated kinases. Results of the present study indicate that both Erk1/2 and PI 3-K/Akt kinase pathways are vital for cytoprotective effect of aniracetam.

Aniracetam attenuates apoptosis of astrocytes subjected to simulated ischemia in vitro

The aim of the present study was to establish whether aniracetam is capable of protecting cultured rat astrocytes against ischemic injury. Treatment of the cultures with aniracetam (1, 10 and 100 mM) during 24 h ischemia simulated in vitro significantly decreased the number of apoptotic cells. The antiapoptotic effects of the drug were confirmed by the increase of intracellular ATP and phosphocreatine (PCr) levels and the inhibition of the caspase-3 activity. Aniracetam also attenuated cellular oxidative stress by decreased production of reactive oxygen species (ROS). These effects were associated with the decrease in levels of c-fos and c-jun mRNA in primary astrocyte cultures exposed to 24 h ischemia. When cultured astrocytes were incubated during 24 h simulated ischemia with wortmannin, a phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor or PD98059, a mitogen-activated protein (MAP)/extracellular signal regulated kinase (ERK) (MEK) inhibitor the cell apoptosis was accelerated. This effect was antagonized by adding 100 mM aniracetam to the culture medium. These findings suggest that the protective effect of aniracetam is mediated by PI 3-kinase and MEK pathways in the downstream mechanisms.