Thioacetamide-induced Hepatic Encephalopathy In Rats Research Articles

Unveiling the protective potential of mirabegron against thioacetamide-induced hepatic encephalopathy in rats: Insights into cAMP/PPAR-γ/p-ERK1/2/p S536 NF-κB p 65 and p-CREB/BDNF/TrkB in parallel with oxidative and apoptotic trajectories

Hepatic encephalopathy (HE) is one of the most prevalent and severe hepatic and brain disorders in which escalation of the oxidative, inflammatory and apoptotic trajectories pathologically connects acute liver injury with neurological impairment. Mirabegron (Mira) is a beta3 adrenergic receptor agonist with proven antioxidant and anti-inflammatory activities. The current research pointed to exploring Mira’s hepato-and neuroprotective impacts against thioacetamide (TAA)-induced HE in rats. Rats were distributed into three experimental groups: the normal control group, the TAA group, received TAA (200 mg/kg/day for three consecutive days) and the Mira-treated group received Mira (10 mg/kg/day; oral gavage) for 15 consecutive days and intoxicated with TAA from the 13th to the 15th day of the experimental period. Mira counteracted hyperammonemia, enhanced rats’ locomotor capability and motor coordination. It attenuated hepatic/neurological injuries by its antioxidant, anti-apoptotic as well as anti-inflammatory potentials. Mira predominantly targeted cyclic adenosine monophosphate (cAMP)/phosphorylated extracellular signal-regulated kinase (p-Erk1/2)/peroxisome proliferator-activated receptor gamma (PPARγ) dependent pathways via downregulation of p S536-nuclear factor kappa B p65 (p S536 NF-κB p 65)/tumor necrosis alpha (TNF-α) axis. Meanwhile, it attenuated nuclear factor erythroid 2-related factor (Nrf2) depletion in parallel with restoring of the neuroprotective defensive pathway by upregulation of cerebral cAMP/PPAR-γ/p-ERK1/2 and p-CREB/BDNF/TrkB besides reduction of GFAP immunoreactivity. Mira showed anti-apoptotic activity through inhibition of Bax immunoreactivity and elevation of Bcl2. To summarize, Mira exhibited a hepato-and neuroprotective effect against TAA-induced HE in rats via shielding antioxidant defense and mitigation of the pathological inflammatory and apoptotic axis besides upregulation of neuroprotective signaling pathways.

Retraction Note: Amelioration of thioacetamide-induced hepatic encephalopathy in rats by low-dose gamma irradiation.

Retraction Note: Amelioration of thioacetamide-induced hepatic encephalopathy in rats by low-dose gamma irradiation.

Protective effects of Tinospora cordifolia miers extract against hepatic and neurobehavioral deficits in thioacetamide-induced hepatic encephalopathy in rats via modulating hyperammonemia and glial cell activation

Ethnopharmacological relevanceTinospora cordifolia (TC) a potential medicinal herb, has been ethnobotanically used as an eco-friendly supplement to manage various diseases, including cerebral fever. Earlier studies have shown that TC exhibits diverse beneficial effects, including hepatoprotective and neuroprotective effects. However, the effects of TC remain unexplored in animal models of encephalopathy including hepatic encephalopathy (HE). Aim of the studyTo evaluate the effects of TC stem extract against thioacetamide (TAA)-induced behavioural and molecular alterations in HE rats. Methods and materialsThe extract was preliminarily screened through phytochemical and HR-LC/MS analysis. Animals were pre-treated with TC extract at doses 30 and 100 mg/kg, orally. Following 7 days of TC pre-treatment, HE was induced by administering TAA (300 mg/kg, i. p. thrice). Behavioural assessments were performed after 56 h of TAA first dose. The animals were then sacrificed to assess biochemical parameters in serum, liver and brain. Liver tissue was used for immunoblotting and histological studies to evaluate inflammatory and fibrotic signalling. Moreover, brain tissue was used to evaluate brain edema, activation of glial cells (GFAP, IBA-1) and NF-κB/NLRP3 downstream signalling via immunoblotting and immunohistochemical analysis in cortex and hippocampus. ResultsThe pre-treatment with TC extract effective mitigated TAA-induced behavioural alterations, lowered serum LFT (AST, ALT, ALP, bilirubin) and oxidative stress markers in liver and brain. TC treatment significantly modulated hyperammonemia, cerebral edema and preserved the integrity of BBB proteins in HE animals. TC treatment attenuated TAA-induced histological changes, tissue inflammation (pNF-κB (p65), TNF-α, NLRP3) and fibrosis (collagen, α-SMA) in liver. In addition, immunoblotting analysis revealed TC pre-treatment inhibited fibrotic proteins such as vimentin, TGF-β1 and pSmad2/3 in the liver. Our study further showed that TC treatment downregulated the expression of MAPK/NF-κB inflammatory signalling, as well as GFAP and IBA-1 (glial cell markers) in cortex and hippocampus of TAA-intoxicated rats. Additionally, TC-treated animals exhibited reduced expression of caspase3/9 and BAX induced by TAA. ConclusionThis study revealed promising insights on the protective effects of TC against HE. The findings clearly demonstrated that the significant inhibition of MAPK/NF-κB signalling and glial cell activation could be responsible for the observed beneficial effects of TC in TAA-induced HE rats.

Green synthesized cerium oxide nanoparticles ameliorate hepatic and cognitive dysfunctions in thioacetamide-induced hepatic encephalopathy in rats: Modulation of TLR-4/NF-κB/Caspase-3 signaling pathways

Green synthesized cerium oxide nanoparticles ameliorate hepatic and cognitive dysfunctions in thioacetamide-induced hepatic encephalopathy in rats: Modulation of TLR-4/NF-κB/Caspase-3 signaling pathways

Indole-3-carbinol ameliorated the thioacetamide-induced hepatic encephalopathy in rats

Indole-3-carbinol (I3C) is reported to have hepatic and neuroprotective properties. However, the I3C role in the protection of the liver and brain in the pathological condition of hepatic encephalopathy has not been investigated. Therefore, in the present study, we have assessed the hepatic and neuroprotective roles of I3C against thioacetamide (TAA)- induced hepatic encephalopathy in Wistar rats. TAA (300 mg/kg) was intraperitoneally administered to Wistar rats to induce hepatic encephalopathy. The elevated levels of ammonia in the blood, liver, and brain were substantially lowered by I3C treatment (25, 50, and 100 mg/kg, oral, 7 days). I3C significantly ameliorated the TAA-induced liver dysfunction by decreasing the alanine transaminase, aspartate transaminase, and alkaline phosphatase enzymes and reduced the elevated cytochrome P4502E1 (CYP2E1) activity in the liver and brain. Further, I3C alleviated mitochondrial dysfunction and oxidative stress in the brain. I3C treatment improved the anti-inflammatory cytokine interleukin (IL)− 10 while reducing inflammatory cytokines such as tumor necrosis factor-1 and IL-6 in hepatic encephalopathy rats. I3C reduced the levels of apoptotic indicators mediated by the mitochondria, including cytochrome c, caspase 9, and caspase 3. Concurrently, I3C mitigated the liver and brain histological abnormalities in hepatic encephalopathy rats. Therefore, the present study concluded that the I3C protected the liver and brain from TAA-induced hepatic encephalopathy injury by inhibiting CYP2E1 enzyme activity and decreasing ammonia, oxidative stress, inflammation, and apoptosis. The present study provides preclinical validation of I3C use as hepatic and neuroprotective for hepatic encephalopathy management.

Naringenin mitigates thioacetamide-induced hepatic encephalopathy in rats: targeting the JNK/Bax/caspase-8 apoptotic pathway.

Hepatic encephalopathy (HE) is a serious neurological disorder which is related to liver dysfunction. HE was induced by thioacetamide (TAA) injection (350 mg kg-1, i.p.) for 3 consecutive days. This study was performed to investigate the prophylactic impact of naringenin against TAA-induced HE. Naringenin (100 mg kg-1) was orally administered for 7 days starting 4 days prior to TAA injection. Naringenin effectively mitigated TAA-induced behavioural, structural and functional alterations. Naringenin ameliorated TAA-induced cognitive impairment as evidenced by the increase in the fall-off time in the rotarod test, decrease in the escape latency in the Morris water maze test and increase in the time spent in the center and in the number of rearing in the open field test. Additionally, naringenin significantly decreased the serum levels of transaminases, alkaline phosphatase, gamma-glutamyl transferase, bile and ammonia. Moreover, naringenin succeeded in reducing the levels of hepatic and cerebral c-Jun N-terminal kinases (JNK) as well as hepatic SORT1 levels. In addition, naringenin successfully elevated the levels of hepatic and cerebral pro-brain-derived neurotrophic factor (pro-BDNF) and BDNF in addition to the cerebral SORT1 level. Finally, naringenin markedly decreased the expression of Bax and caspase-8 as presented by the immunohistochemical results. Collectively, the ameliorative effect of naringenin on the development of HE might be attributed to the modulation of the JNK/Bax/caspase-8 apoptotic pathway.

Hepatoprotective and cognitive-enhancing effects of hesperidin against thioacetamide-induced hepatic encephalopathy in rats

Hepatic encephalopathy (HE) is a serious neurological disorder which might occur in both acute and chronic liver injury. Aims: This study was carried out to explore the protective effects of hesperidin against experimentally induced HE. Main methods: Rats were sorted into four groups each of six; Normal group, TAA group: rats were administered 350 mg/kg of TAA i.p. from day 5 to day 7. TAA+ Hesp 100 group: rats were administered hesperidin 100 mg/kg/day orally for 7 days along with i.p TAA injection 350 mg/kg from day 5 to 7. TAA+ Hesp 200 group: rats were administered hesperidin 200 mg/kg/day orally for 7 days along with i.p TAA injection 350 mg/kg from day 5 to 7. Liver function, oxidative stress biomarkers, behavioral tests in addition to histopathological examination were assessed. Key findings: Hesperidin efficiently mitigated TAA-induced HE as evidenced by significant reduction in liver enzymes, bile and ammonia levels in serum. Moreover, hesperidin restored oxidant/antioxidant balance as manifested by reduction in MDA content in both cerebral and hepatic tissues. Additionally, hesperidin improved motor and cognitive abilities besides tissues' architecture as demonstrated by behavioral tests and histopathology results, respectively. Hesperidin also decreased levels of NLRP3 and increased levels of Sirt1 and FOXO in both cerebral and hepatic tissues. Finally, hesperidin markedly decreased the expression of IL-1β and caspase-1 as shown by immunohistochemical results. Significance: Taken together, the hepatoprotective impact of hesperidin and its ameliorative effect on the progression of HE appear to be mediated by its modulatory influence on NLRP3/Sirt1/FOXO signaling.

Phytochemical constituents and protective efficacy of Schefflera arboricola L. leaves extract against thioacetamide-induced hepatic encephalopathy in rats

Context Hepatic encephalopathy (HE) is a severe neuropsychiatric syndrome resulting from liver failure. Objective To evaluate the protective effect of Schefflera arboricola L. leaves methanol extract against thioacetamide (TAA) induced HE in rats. Materials and methods GC/MS, LC-ESI-MS, and the total phenolic and flavonoid contents were determined. The methanol extract was orally administrated (100 and 200 mg/kg body weight) for 21 days. TAA (200 mg/kg body weight) was given intraperitoneally on day 19 and continued for three days. The evaluation was done by measuring alanine aminotransferase (ALT), alkaline phosphatase (ALP), ammonia, reduced glutathione (GSH), malondialdehyde (MDA), nitric oxide (NO), tumour necrosis factor-alpha (TNF-α), toll-like receptor 4 (TLR4), interleukin-1 beta (IL-1β), interlukin-6 (IL-6), cyclooxygenase 2 (COX2), B cell lymphoma 2 (BCL2), alpha-smooth muscle actin (α-SMA), and the cluster of differentiation 163 (CD163). The histological features of the liver and brain were conducted. Results Forty-five compounds were identified from the n-hexane fraction, while twenty-nine phenolic compounds were determined from the methanol extract. Pre-treatment with the plant extract returned most of the measurements under investigation to nearly normal. Conclusion Due to its richness with bioactive compounds, Schefflera arboricola L. leaves methanolic extract succeeded to exert anti-fibrotic, anti-inflammatory, and antioxidants properties in TAA-induced HE in rats with more efficacy to its high protective dose.

Linagliptin attenuates thioacetamide-induced hepatic encephalopathy in rats: Modulation of C/EBP-β and CX3CL1/Fractalkine, neuro-inflammation, oxidative stress and behavioral defects

The degree of neuroinflammation is correlated mainly with cognitive and motor dysfunctions associated with hepatic encephalopathy (HE). The current study was conducted to explore the possible protective potential of the antidiabetic drug; linagliptin (LNG; 10 or 20 mg/kg) against HE induced by thioacetamide (TAA) in rats. Animals received two consecutive intraperitoneal injections of TAA (200 mg/kg) on alternate days. Neurobehavioral tests were performed 24 h after the last injection, and rats were sacrificed 24 h later (48 h). The higher LNG dose more effectively protected against TAA-induced changes. Administration of LNG for 15 days before TAA notably mitigated TAA-induced acute liver injury and HE, as verified by the marked improvement in motor coordination, locomotor activity, and cognition function. LNG maintained both brain and liver weight indices and retracted the hyperammonemia with a prominent suppression in liver transaminases. This was accompanied by an evident modulation of hepatic and hippocampal oxidative stress markers; GSH and MDA. LNG attenuated both liver and hippocampal pro-inflammatory cytokine; IL-1β while augmented the anti-inflammatory one; IL-10. It noticeably reduced hepatic and hippocampal COX-2 and TNF-α and maintained hepatic and brain architectures. It also induced a marked decrease in the inflammation-regulated transcription factor, C/EBP-β, with a profound increase in hippocampi's anti-inflammatory chemokine, CX3CL1/Fractalkine. LNG modulated TAA-induced disturbances in hippocampal amino acids; glutamate, and GABA with a significant increase in hippocampal BDNF. In conclusion, the regulatory effect of LNG on neuroinflammatory signaling underlines its neuroprotective effect against progressive encephalopathy accompanying acute liver injury.

Flavonoids from Barnebydendron riedelii leaf extract mitigate thioacetamide-induced hepatic encephalopathy in rats: The interplay of NF-κB/IL-6 and Nrf2/HO-1 signaling pathways

Phytochemical investigation of the butanol fraction (BUF) derived from the 70% aqueous methanolic leaf extract of Barnebydendron riedelii led to the isolation of three flavonoid glycosides; kaempferol-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside, quercetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-galactopyranoside and quercetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside. Docking studies were fulfilled to validate the possible bio-properties of BUF toward nuclear factorkappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2). The protective role of BUF against behavioral, biochemical, molecular, histopathological and immunohistochemical alterations in thioacetamide (TAA)-induced hepatic encephalopathy in rats was investigated. The toxicological studies indicated that BUF was safe up to 2000 mg/kg bw. Prior to TAA intoxication, rats were orally treated with either BUF at multiple doses (70, 140 and 280 mg/kg bw) or lactulose (8 mL/kg bw) for 14 consecutive days. On the 13th and the 14th day, TAA (200 mg/kg bw/day) was intraperitoneally injected. The BUF significantly improved motor impairment, ameliorated cognitive deficits and attenuated TAA-induced hepatotoxicity. Moreover, BUF controlled the inflammatory processes by suppressing the hepatic inflammatory cytokine; interleukin-6 (IL-6) as well as its pro-inflammatory mediator; NF-κB supporting the molecular docking assessment. The brain neurotransmitters; dopamine, serotonin and noradrenaline, as well as ammonia levels were improved in BUF-treated TAA-intoxicated animals in a dose-dependent manner. Furthermore, BUF administration to TAA-intoxicated rats modulated the Nrf2 and heme oxygenase 1 (HO-1) genes expression in liver and brain tissues. The histological evaluation showed that pretreatment of TAA-intoxicated rats with BUF ameliorated the degenerative effects of TAA on liver and brain tissues as well as reduced the activation of cellular apoptotic marker; caspase-3 and glial fibrillary acidic protein (GFAP+) astrocytes. In conclusion, the observed hepato-neuroprotective effect of BUF is attributed to its flavonoidal content through its modulatory effects on of NF-κB/IL-6 and Nrf2/HO-1 signaling pathways.

Synergistic effect of aminoguanidine and l-carnosine against thioacetamide-induced hepatic encephalopathy in rats: behavioral, biochemical, and ultrastructural evidence.

Hepatic encephalopathy depicts the cluster of neurological alterations that occur during acute or chronic hepatic injury. Hyperammonemia, inflammatory injury, and oxidative stress are the main predisposing factors for the direct and indirect changes in cerebral metabolism causing encephalopathy. The aim of this study was to evaluate the possible synergistic effect between aminoguanidine (AG; 100 mg/kg, p.o.) and l-carnosine (CAR; 200 mg/kg, p.o.) on hepatic encephalopathy that was induced by thioacetamide (TAA; 100 mg/kg, i.p.) administered three times weekly for six weeks. Behavioral changes, biochemical parameters, histopathological analysis, and immunohistochemical and ultrastructural studies were conducted 24h after the last treatment. Combining AG with CAR improved TAA-induced locomotor impairment and motor incoordination evidenced by reduced locomotor activity and decline in motor skill performance, as well as ameliorated cognitive deficits. Moreover, both drugs restored the levels of serum hepatic enzymes and serum and brain levels of ammonia. In addition, the combination significantly modulated hepatic and brain oxidative stress biomarkers, inflammatory cytokines, and cleaved caspase-3 expression. Furthermore, they succeeded in activating nuclear erythroid 2-related factor 2 (Nrf2) expression and heme oxygenase-1 (HO-1) activity and ameliorating markers of hepatic encephalopathy, including hepatic necrosis and brain astrocyte swelling. This study shows that combining AG with CAR exerted a new intervention for hepatic and brain damage in hepatic encephalopathy due to their complementary antioxidant, anti-inflammatory effects and hypoammonemic effects via Nrf2/HO-1 activation and NO inhibition.

Amelioration of thioacetamide-induced hepatic encephalopathy in rats by low-dose gamma irradiation.

Brain affection is a common symptom of liver insufficiency. This study aimed to evaluate the role of low-dose γ irradiation (LDR) as a potential therapeutic agent in thioacetamide (TAA)-induced hepatic encephalopathy (HE) in rats. Effects of local and whole-body irradiation (0.5Gy) on rat brain/liver were evaluated following the induction of HE by TAA (200mg/kg/day/for 3 successive days). Serum activities of aspartate transaminase (AST) and alanine transaminase (ALT) and ammonia level were assessed. The effect of HE on brain was evaluated through the determination of brain contents of malondialdehyde (MDA), reduced glutathione (GSH), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β) and glutathione peroxidase (GPx) activity. Moreover, apoptotic and inflammatory changes in brain and liver tissues were assessed together with alpha-smooth muscle actin (α-SMA); fibrosis marker. Results showed correction of the biochemical parameters which was supported by the results of the immunohistochemical examinations. LDR is a promising hepato- and neurotherapy against HE.

Protective role of chrysin on thioacetamide-induced hepatic encephalopathy in rats

Hepatic encephalopathy (HE) is a serious neuropsychiatric syndrome due to either acute or chronic hepatic failure. This study aimed to investigate the possible neuroprotective effect of chrysin, a natural flavenoid on thioacetamide (TAA)-induced hepatic encephalopathy in rats. Also the effect of chrysin on motor impairment, cognitive deficits, oxidative stress, neuroinflammation, apoptosis and histopathological damage was assessed. HE was induced in Wistar rats by intraperitoneal (i.p.) injection of TAA (200 mg/kg) for three alternative days. Normal and control groups received the vehicle for 21 days. Chrysin was administered orally for 21 days (25, 50, 100 mg/kg) and starting from day 17, rats received i.p. dose of TAA (200 mg/kg) at three alternative days. Then behavioral, biochemical, histopathological and immunohistochemical analyses were conducted. Chrysin improved TAA-induced motor incoordination as it reduced final falling latency time in rotarod test, ameliorated cognitive deficits in object recognition test (ORT) and attenuated serum ammonia, hepatic liver enzymes namely, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), reduced malondialdehyde (MDA), elevated reduced glutathione (GSH), reduced nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) brain contents. Chrysin administration also reduced Toll-4 receptor (TLR-4) gene expression, caspase-3 protein expression, hepatic necrosis and astrocyte swelling. This study depicts that chrysin exerted neuroprotective effect in TAA-induced HE rats, evidenced by improvement of cognitive deficits, motor incoordination and histopathological changes such as astrocyte swelling and vacuolization; hallmarks in HE, via reducing hyperammonia, ameliorating hepatic function, in addition to its anti-oxidant, inactivation of TLR-4/NF-κB inflammatory pathway, and anti-apoptotic effects.

Protective effects of trimetazidine on thioacetamide-induced hepatic encephalopathy in rats

Protective effects of trimetazidine on thioacetamide-induced hepatic encephalopathy in rats

Finasteride Has Regionally Different Effects on Brain Oxidative Stress and Acetylcholinesterase Activity in Acute Thioacetamide-Induced Hepatic Encephalopathy in Rats.

Finasteride (FIN) inhibits neurosteroid synthesis and potentially improves the course of hepatic encephalopathy (HE). This study aimed to investigate the effects of FIN on brain oxidative stress and acetylcholinesterase (AchE) activity in acute thioacetamide-induced HE in rats. Male Wistar rats were divided into groups: 1. control; 2. thioacetamide-treated group (TAA; 900 mg/kg); 3. finasteride-treated group (FIN; 150 mg/kg); 4. group treated with FIN and TAA (FIN+TAA). Daily doses of FIN (50 mg/kg) and TAA (300 mg/kg) were administered intraperitoneally during three days and in FIN+TAA group FIN was administered 2h before every dose of TAA. FIN pretreatment prevented TAA-induced rise in malondialdehyde level in the cortex due to restoration of catalase activity and increased expression of superoxide dismutase 1 (SOD1) and induced an increase in malondialdehyde level in the thalamus due to reduction of glutathione peroxidase (GPx) and glutathione reductase (GR) activity. Although FIN pretreatment did not affect malondialdehyde level in hippocampus and caudate nucleus, hippocampal SOD1 expression was higher (p<0.05) and GR activity lower in FIN+TAA vs. TAA group (p<0.05). GPx activity was lower in caudate nucleus in FIN+TAA vs. TAA group (p<0.01). FIN pretreatment prevented TAA-induced rise in AchE activity in the thalamus and caudate nucleus and AchE activity correlates inversely in the thalamus (p<0.05) and positively in caudate nucleus (p<0.01) with malondialdehyde level. FIN has regionally selective effects on oxidative stress and AchE activity in the brain in acute TAA-induced HE in rats. The prooxidant role of FIN in the thalamus may be causally linked with inhibition of AchE.

22. The effects of finasteride on behavioral changes in thioacetamide-induced hepatic encephalopathy in rats

Purpose: The purpose of our study was to investigate the effects of finasteride on behavioral characteristics of thioacetamide-induced hepatic encephalopathy (HE) in rats. Methods: Male Wistar rats were divided into following groups: 1. Control; 2. Thioacetamide-treated group, TAA (900 mg/kg); 3. Finasteride-treated group, FIN (150 mg/kg); 4. FIN + TAA group treated with FIN and TAA. Daily doses of TAA (300 mg/kg) and FIN (50 mg/kg) were injected during three subsequent days intraperitoneally and every dose of FIN was administered 2 h before TAA in FIN + TAA group. Behavioral changes were followed 0, 2, 4, 6 and 24 h after treatment. Results: While corneal, withdrawal, grasping and righting reflex were significantly diminished in TAA vs. control group ( p p p p Conclusion: Finasteride pretreatment improves motor activity and prevents development of coma in TAA-induced HE in rats.

Effects of caffeic acid phenethyl ester on thioacetamide-induced hepatic encephalopathy in rats

Hepatic encephalopathy (HE) is a major neurological complication secondary to severe liver failure. The aim of the present study was to examine the possible neuroprotective effects of caffeic acid phenethyl ester (CAPE) with or without laxative treatment against thioacetamide-induced HE by investigating behavioral and motor activities in rats as well as blood ammonia level and oxidant–antioxidant parameters of cortex, brain stem and cerebellum. After induction of HE by thioacetamide, the rats were treated with lactulose, CAPE (CAPE treatment was started one day before the first dose of thioacetamide) or CAPE plus lactulose. The behavioral and motor scales were measured at the 54th hour after the first thioacetamide injection, the blood samples and brains were taken under anesthesia at the 60th hour for biochemical analysis. The survival rates were 37.5% in HE group, 70% in HE + lactulose group, 80% in HE + CAPE group, and 100% in HE + CAPE + lactulose group. Increased ammonia, ALT and AST levels in blood along with impaired sensory-motor behavior tests were reversed to proximate control values in CAPE + lactulose treated group. There were increased lipid peroxidation and protein oxidation and decreased antioxidant enzyme activities in almost all brain parts of HE group. CAPE or lactulose treatment alone ameliorated those oxidant and antioxidant parameters; however, CAPE treatment together with lactulose reversed them to almost control level. In conclusion, thioacetamide-induced HE injury in rats was reversed almost fully by CAPE and laxative combination. There was no death in CAPE and laxative treated group animals and it may be due to the direct neuroprotective effect of CAPE together with the prevention of the body from ammonia production.

Synaptosomal uptake of alpha-ketoglutarate and glutamine in thioacetamide-induced hepatic encephalopathy in rats.

The kinetics of uptake of two astroglia-derived glutamate (GLU) precursors, alpha-ketoglutarate (alpha-KG) and glutamine (GLN) were determined in synaptosomes derived from rats with acute hepatic encephalopathy (HE) induced with a hepatotoxin, thioacetamide (TAA). TAA treatment increased by 33% Vmax for high affinity, low capacity alpha-KG uptake, without influencing its Km. The increase of the uptake capacity for alpha-KG may represent a response of the GLUergic nerve terminals to the decreased cerebral alpha-KG content, which during HE is associated with depressed activity of pyruvate carboxylase, an enzyme that replenishes alpha-KG in astrocytes. The result is thus consistent with the notion that HE affects the astroglial control of GLUergic neurotransmission. The Km and Vmax for the low affinity, high capacity GLN uptake was not affected by TAA treatment.

Taurine release from brain slices in thioacetamide-induced hepatic encephalopathy in rats

The possible involvement of taurine in the pathogenesis of hepatic encephalopathy was studied in rats injected with thioacetamide. Spontaneous release of exogenous labeled taurine was not affected in any brain area studied, but the potassium-stimulated release was enhanced in the striatum in thioacetamide-treated rats. High concentrations of ammonium ions also evoked greater release of taurine from striatal slices in rats with thioacetamide-induced hepatic encephalopathy.