Comparative Investigation of Protective Effects of Metyrosine and Metoprolol Against Ketamine Cardiotoxicity in Rats

Chlorogenic Acid Attenuates Doxorubicin-Induced Oxidative Stress and Markers of Apoptosis in Cardiomyocytes via Nrf2/HO-1 and Dityrosine Signaling

(1) Background: Doxorubicin (DOX) is extensively used for cancer treatments; however, its clinical application is limited because of its cardiotoxic adverse effects. A combination of DOX and agents with cardioprotective properties is an effective strategy to ameliorate DOX-related cardiotoxicity. Polyphenolic compounds are ideal for the investigation of novel cardioprotective agents. Chlorogenic acid (CGA), an essential dietary polyphenol found in plants, has been previously reported to exert antioxidant, cardioprotective, and antiapoptotic properties. The current research evaluated CGA's in vivo cardioprotective properties in DOX-induced cardiotoxicity and the probable mechanisms underlying this protection. (2) Methods: CGA's cardioprotective properties were investigated in rats that were treated with CGA (100 mg/kg, p.o.) for fourteen days. The experimental model of cardiotoxicity was induced with a single intraperitoneal (15 mg/kg i.p.) injection of DOX on the 10th day. (3) Results: Treatment with CGA significantly improved the DOX-caused altered cardiac damage markers (LDH, CK-MB, and cTn-T), and a marked improvement in cardiac histopathological features accompanied this. DOX downregulated the expression of Nrf2/HO-1 signaling pathways, and the CGA reversed this effect. Consistently, caspase-3, an apoptotic-related marker, and dityrosine expression were suppressed, while Nrf2 and HO-1 expressions were elevated in the cardiac tissues of DOX-treated rats after treatment with the CGA. Furthermore, the recovery was confirmed by the downregulation of 8-OHdG and dityrosine (DT) expressions in immunohistochemical findings. (4) Conclusions: CGA demonstrated a considerable cardioprotective effect against DOX-induced cardiotoxicity. One of the possible mechanisms for these protective properties was the upregulation of the Nrf2/HO-1-dependent pathway and the downregulation of DT, which may ameliorate oxidative stress and cardiomyocyte apoptosis. These findings suggest that CGA may be cardioprotective, particularly in patients receiving DOX-based chemotherapy.

The effects of metyrosine on ischemia-reperfusion-induced oxidative ovarian injury in rats: Biochemical and histopathological assessment

The aim of this study is to investigate the effect of metyrosine on ischemia-reperfusion (I/R) induced ovarian injury in rats in terms of biochemistry and histopathology. Rats were divided into: ovarian I/R (OIR), ovarian I/R+50 mg/kg metyrosine (OIRM) and sham (SG) operations. OIRM group received 50 mg/kg metyrosine one hour before the application of the anesthetic agent, OIR and SG group rats received equal amount of distilled water to be used as a solvent orally through cannula. Following the application of the anesthetic agent, ovaries of OIRM and OIR group rats were subjected to ischemia and reperfusion, each of which took two hours. This biochemical experiment findings revealed high levels of malondialdehyde (MDA) and cyclo-oxygenase-2 (COX-2) and low levels of total glutathione (tGSH), superoxide dismutase (SOD) and cyclo-oxygenase-1 (COX-1) in the ovarian tissue of OIR group, with significant histopathological injury. In metyrosine group, MDA and COX-2 levels were lower than the OIR group whereas tGSH, SOD and COX-1 levels were higher, with slighter histopathological injury. Our experimental findings indicate that metyrosine inhibits oxidative and pro-inflammatory damage associated with ovarian I/R in rats. These findings suggest that metyrosine could be useful in the treatment of ovarian injury associated with I/R.

Post-Partum Depression Lactating Rat Model for Evaluating Ketamine's Safety as a Pharmacotherapeutic Treatment: Roles in Cardiac and Urinary Function

Depression is one of the world's most common and mentally disabling illnesses. Post-partum depression is a subtype of depression that affects one in seven women worldwide. Successful pharmacological treatment must consider the consequences for both, since the mother-child bond is fundamental for the well-being of both mother and infant as well as the general development of the newborn. Changes in maternal physiology and/or behavior can significantly influence the development of breastfed infants. Ketamine has been extensively studied for use as an antidepressant due to its mixed mechanisms of action. Safety and efficacy studies in the cardiovascular and urinary systems of a lactating postpartum depression animal model are essential for contributing toward ketamine's clinical use in the respective patient population. Thus, this project aimed to study the implications of postpartum maternal exposure to ketamine during lactation on the cardiovascular system of female rats submitted to the depression induction model by maternal separation. This model promotes depressive effects through stress caused by the interruption of mother-infant bond early in the offspring's life. To achieve depression, each dam was separated from her offspring for 3 h per day, from post-natal day 2 (PND2) to PND12. Experimental groups received daily treatment with either 5, 10, or 20 mg/kg of ketamine intraperitoneally during the lactation period, from PND2 to PND21. Behavioral tests consisted of the maternal and aggressive maternal behavior tests, the olfactory preference test, and the forced swim test. A technique for the detection of catecholamines and indoleamines in the heart muscle was developed for the experimental model groups. The histopathological evaluation was performed on these animals' cardiac muscles and urinary bladders. Our findings suggest that ketamine is safe for use in postpartum depression and does not induce cardiovascular and/or urinary systems toxicity.

Evaluation of the effects of two anaesthetic protocols on oxidative status and DNA damage in red-eared sliders (Trachemys scripta elegans) undergoing endoscopic coeliotomy

The aim of this study was to assess how red-eared sliders (Trachemys scripta elegans) respond to anaesthesia itself and coelioscopy. For that purpose, the turtles were anaesthetised with ketamine-medetomidine or propofol, and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) and the level of malondialdehyde (MDA) were determined by spectrophotometry. The possible genotoxic effects of the anaesthetic agents were estimated by comet assay. A total of 24 turtles were included in this study. The animals were divided into four groups according to the anaesthetic protocol and according to whether endoscopy would be performed. Significantly decreased activities of CAT were found only in the propofol group and in turtles undergoing coelioscopy. Both anaesthetic protocols induced significantly increased MDA levels, while no differences were observed after the intervention. A significant increase in GST activity was detected in turtles after both anaesthetic protocols, but after coelioscopy significant changes in GST activity were found only in the propofol group. However, no differences in SOD activity and no DNA damages were detected in either group. These findings suggest that ketamine-medetomidine may be more suitable anaesthetic agents in red-eared sliders than propofol.

Protective effect of oleuropein on ketamine-induced cardiotoxicity in rats

The antioxidant and cardioprotective effects of oleuropein have been reported in several studies; however, its effect on ketamine cardiotoxicity has not been known yet. The aim of this study was to investigate the effects of oleuropein in ketamine-induced cardiotoxicity model in rats. A total of 28 male Wistar Albino rats were included in the study and they were randomly divided into four groups, each having seven rats. Group 1 (control): rats were given 1 mL of DMSO by oral gavage method for 7 days. Group 2 (ketamine): on the seventh day of the study, 60 mg/kg ketamine was administered intraperitoneally. Then, 60 mg/kg ketamine was administered intraperitoneally every 10 min for 3 h. Group 3 (oleuropein): rats were given 200 mg/kg/day oleuropein by oral gavage method for 7 days. Group 4 (oleuropein + ketamine): rats were given 1 × 200 mg/kg oleuropein by oral gavage method for 7 days. Furthermore, 60 mg/kg ketamine was administered intraperitoneally on the seventh day of the experiment. Then, 60 mg/kg ketamine was administered intraperitoneally every 10 min for 3 h. Serum cardiac marker (TnI, CK-MB and CK) levels were measured. Histopathological analysis was performed on a portion of the cardiac tissue. Cardiac tissue oxidative stress and antioxidant markers (MDA, GSH, GSH.Px and CAT), TNF-α, IL-6, NF-κB, COX-2 and Nrf-2 gene expressions, and protein conversion levels of related genes were determined. Data obtained showed that ketamine administration increased MDA (p < 0.001), TNF-α (p < 0.01), IL-6 (p < 0.01), COX-2 (p < 0.001) and NF-κB (p < 0.001) levels, as well as serum TnI (p < 0.001), CK-MB (p < 0.001) and CK (p < 0.01) levels whereas decreased GSH (p < 0.05) and Nrf-2 (p < 0.05) levels, as well as GSH-Px (p < 0.001) and CAT (p < 0.05) enzyme activities. Oleuropein administration was observed to decrease MDA, TNF-α, IL-6, COX-2, NF-κB, TnI, CK-MB and CK levels close to the control group and to increase GSH levels and GSH-Px and CAT enzyme activities close to the control group. This study showed that oleuropein administration reversed the increased oxidative stress and inflammation as a result of the use of ketamine and had protective effects on the heart.

The effects of ketamine and thiopental used alone or in combination on the brain, heart, and bronchial tissues of rats

INTRODUCTION

We compared the side effects of ketamine and thiopental used alone and of a ketamine/thiopental combination dose on the brain,heart, and bronchial tissues of rats.

MATERIAL AND METHODS

Three groups received intraperitoneal injections of 30 mg/kg ketamine (K-30); 15 mg/kg thiopental (T-15); or of both in combination (KTSA). These doses were doubled in another set of study groups (K-60, T-30, and KTA groups, respectively). Optimal anesthesia duration was examined in all groups.

RESULTS

Anesthesia did not occur with 30 mg/kg ketamine or 15 mg/kg thiopental. However, when used alone ketamine and thiopental led to oxidative stress in the striatum, heart, and bronchial tissues. Conversely, combined administration of anesthetics and subanesthetic doses were found not to create oxidative stress in any of these areas. The highest level of adrenaline in blood samples collected from the tail veins was measured in the KTA-60, and the lowest amount in the T-30. Creatine kinase activity was highest in the KTA-60 group (p < 0.001). When we compared for all 5 groups to untreated control group; the creatine kinase-MB activities were significiantly different in K-30, T-15 and T-30 (p < 0.001).

CONCLUSIONS

The studied doses of ketamine led to oxidative stress by increasing the amount of adrenaline. Thiopental increased oxidative stress with decreases in adrenaline. A longer anesthetic effect with minimal adverse events may be achieved by ketamine and thiopental in combination.

Mechanistic studies on ketamine-induced mitochondrial toxicity in zebrafish embryos

Ketamine, a phencyclidine derivative, is an antagonist of the Ca²⁺-permeable N-methyl-d-aspartate (NMDA)-type glutamate receptors. It is a pediatric anesthetic and has been implicated in developmental neurotoxicity. Ketamine has also been shown to deplete ATP in mammalian cells. Our previous studies showed that acetyl l-carnitine (ALCAR) prevented ketamine-induced cardiotoxicity and neurotoxicity in zebrafish embryos. Based on our finding that ALCAR's protective effect was blunted by oligomycin A, an inhibitor of ATP synthase, we further investigated the effects of ketamine and ALCAR on ATP levels, mitochondria and ATP synthase in zebrafish embryos. The results demonstrated that ketamine reduced ATP levels in the embryos but not in the presence of ALCAR. Ketamine reduced total mitochondrial protein levels and mitochondrial potential, which were prevented with ALCAR co-treatment. To determine the cause of ketamine-induced ATP deficiency, we explored the status of ATP synthase. The results showed that a subunit of ATP synthase, atp5α1, was transcriptionally down-regulated by ketamine, but not in the presence of ALCAR, although ketamine caused a significant upregulation in another ATP synthase subunit, atp5β and total ATP synthase protein levels. Most of the ATP generated by heart mitochondria are utilized for its contraction and relaxation. Ketamine-treated embryos showed abnormal heart structure, which was abolished with ALCAR co-treatment. This study offers evidence for a potential mechanism by which ketamine could cause ATP deficiency mediated by mitochondrial dysfunction.