Potential therapeutic antipsychotic effects of Naringin against ketamine-induced deficits in rats: Involvement of Akt/GSK-3ß and Wnt/ß-catenin signaling pathways.

AIM: Schizophrenia is a chronic, disabling and one of the major neurological illnesses affecting nearly 1% of the global population. Currently available antipsychotic medications possess limited effects. The current research aimed at investigating potential therapeutic add-on benefit to enhance the effects of clozapine anti-schizophrenic. MAIN METHODS: To induce schizophrenia, ketamine was administered at a dose of 25 mg/kg i.p. for 14 consecutive days. Naringin was administered to Wistar rats at a dose of 100 mg/kg orally, alone or in combination with clozapine 5 mg/kg i.p from day 8 to day 14. Furthermore, behavioral tests were conducted to evaluate positive, negative and cognitive symptoms of schizophrenia. In addition, neurotransmitters' levels were detected using HPLC. Moreover, oxidative stress markers were assessed using spectrophotometry. Furthermore, apoptotic and wnt/ß-catenin pathway markers were determined using western blotting (Akt, GSK-3ß and ß-catenin), colorimetric methods (Caspase-3) and immunohistochemistry (Bax, Bcl2 and cytochrome c). KEY FINDINGS: Ketamine induced positive, negative and cognitive schizophrenia symptoms together with neurotransmitters' imbalance. In addition, ketamine treatment caused significant glutathione depletion, lipid peroxidation and reduction in catalase activity. Naringin and/or clozapine treatment significantly attenuated ketamine-induced schizophrenic symptoms and oxidative injury. Additionally, ketamine provoked apoptosis via increasing Bax/Bcl2 expression, caspase-3 activity, and Cytochrome C and Akt protein expression while naringin/clozapine treatment significantly inhibited this apoptotic effect. Moreover, naringin activated the neurodevelopmental wnt/ß-catenin signaling pathway evidenced by increasing pGSK-3ß and reducing pß-catenin protein expression. SIGNIFICANCE: These findings may suggest that naringin possesses a potential therapeutic add-on effect against ketamine-induced schizophrenia.

Anti-fibrotic potential of a Matthiola arabica isothiocyanates rich fraction: impact on oxidative stress, inflammatory and fibrosis markers.

The present study is the first one to investigate the glucosinolates (GLS) profile and anti-fibrotic effect of isothiocyanates (ITCs) rich fraction of Matthiola arabica (Brassicaceae) using an experimental model of liver fibrosis in rats. Five GLS (ethyl glucosinolate, gluconapin, glucodehydroerucin, glucoerucin and glucoraphanin) were identified by gas liquid chromatography-mass spectrometric (GLC-MS) analysis of their hydrolysis products, produced by the natural autolysis and exogenous myrosinase hydrolysis using one and two units of the enzyme. Spectrophotometric determination of the total intact GLS revealed that content in the fresh sample was 1.8 times higher than in the dry one. ITCs rich fraction was prepared by natural autolysis of the fresh aerial part. Male albino rats were given carbon tetrachloride (CCl4) (0.5 ml/kg, twice a week) and/or ITCs -rich fraction (30 mg/ kg, three times a week) for six weeks. Liver function, different oxidative stress, inflammatory and fibrosis markers were investigated. Treatment of animals with ITCs rich fraction significantly counteracted the changes in liver function induced by CCl4. Histopathological examination under both light and electron microscope showed the anti-fibrotic effect of ITCs rich fraction. This finding was confirmed with the markedly improved liver fibrosis markers with ITCs rich fraction co-treatment. In elucidation of anti-fibrotic mechanisms of ITCs rich fraction, the significant glutathione depletion and lipid peroxidation caused by CCl4 intoxication was restored by ITCs rich fraction co-treatment. Besides, ITCs rich fraction showed an anti-inflammatory effect through its ability to counteract the significant increase in nuclear factor kappa B (NF-κB), cyclooxygenase-2 (COX-2) expression, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) levels in liver tissue that caused by CCl4 intoxication. These findings indicate that ITCs-rich fraction of M. arabica possesses a promising anti-fibrotic effect which can be attributed to its antioxidant and anti-inflammatory properties.

A comparative study of protective mechanisms of glycine and L-arginine against cisplatin-induced nephrotoxicity in rat renal cortical slices.

Amino acids exert nephroprotective effects in various forms of acute renal injury depending on their renal hemodynamic effects. The present study was designed to elucidate and compare the role of non hemodynamic mechanisms in protective actions afforded by glycine and L-arginine against cisplatin (CDDP)-induced nephrotoxicity using rat renal cortical slices (RCS). We have investigated the possible modulatory effect of glycine and L-arginine on oxidative stress and necrosis induced by CDDP as well as on CDDP uptake by kidney. After 4 h of incubation with 2 mM CDDP, nephrotoxicity was demonstrated by significant increased lactate dehydrogenase leakage, decreased ability of the slices to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, increased lipid peroxides and depleted reduced glutathione. Also, CDDP significantly inhibited pyruvate-stimulated gluconeogenesis. Histopathological examination of RCS confirmed the occurrence of tubular coagulative necrosis in cortex and corticomedullary regions. Preincubation of RCS with 1 mM glycine or L-arginine 1 h before CDDP addition significantly attenuated the oxidative stress and tubular necrotic effects of CDDP. L-Arginine showed greater antioxidant properties while glycine showed a greater antinecrotic effect. Moreover, the nephroprotective effect was mediated through lowering the platinum uptake by RCS. However, they could not counteract the inhibition of gluconeogenesis induced by CDDP. In conclusion, the present study sheds light on the mechanisms involved in glycine and L-arginine nephroprotection.

Toward gene therapy of premature ovarian failure: intraovarian injection of adenovirus expressing human FSH receptor restores folliculogenesis in FSHR(-/-) FORKO mice.

A homozygous missense mutation, C566T, in the follicle stimulation hormone receptor (FSHR) gene has been linked to premature ovarian failure. The disease leads to infertility in a normal karyotype female with an elevated follicle stimulating hormone (FSH) and decreased serum estrogen level. Female mice carrying mutated FSHR gene, called follitropin receptor knockout (FORKO), display similar phenotype and are sterile because of a folliculogenesis block at a primary stage. We investigated the effects of bilateral intra-ovarian injection of an adenovirus expressing a normal copy of human FSHR on the reproductive system of 6-10 weeks female FORKO mice. Ad-LacZ was injected directly into each ovary of the control group. Animals were sacrificed at 2, 4, 8 and 12 weeks post-injection and tissues collected for evaluation. Treated mice showed estrogenic changes in daily vaginal smear whereas control animals remained fixated in the diestrus stage. Histological evaluation showed on average 26 +/- 4 follicles/ovary in treated group with 8 +/- 2 follicles at the antral stage compared with only 5 +/- 2 with zero follicles at antral stage in Ad-LacZ control mice. There was no significant change in serum level of progesterone, however, estrogen level increased 2-3-fold (P < 0.02) and FSH decreased by up to 50% (P < 0.04) in treated animals. FSHR mRNA was detected in the ovaries of the treated group. In conclusion, intra-ovarian injection of an adenovirus expressing human FSHR gene is able to restore FSH responsiveness and reinitiate ovarian folliculogenesis as well as resume estrogen production in female FORKO mice. Ad-LacZ injections indicate the absence of systemic viral dissemination or germ line transmission of adenovirus DNA to offspring.

The potential therapeutic effect of nitric oxide modulators in experimentally-induced gastric ulcers.

Nitric oxide (NO) appears to play a critical role in modulating gastric mucosal defense. Administration of NO donors has been reported to protect the gastrointestinal mucosa against damage induced by several irritants. However, the possible role of NO in healing existing ulcers must be clarified further. Therefore, the present study was designed to assess the effect of modulation of NO on the healing of an indomethacin-induced peptic ulcer using a NO precursor, L-arginine, and a competitive inhibitor of NO synthase, L-NAME. Results of administering L-arginine were compared to those using nitroglycerin (NTG), an NO donor. Rats were injected with a single oral dose of indomethacin (30 mg/kg) and then treated with L-arginine (200 mg/kg, i.p.), NTG (1 mg/kg, i.p.) or L-NAME (15 mg/kg, i.p.) once daily for 7 d starting 4 h after the indomethacin injection. Gross lesion examination and histological assessment were done. NO, prostaglandin (PGE2), and mucin content in gastric tissue were detected. In addition, oxidative stress markers including glutathione (GSH) and lipid peroxides were measured. L-arginine and NTG almost completely healed indomethacin-induced ulceration as indicated by macroscopic and histological examination, restoration of normal levels of NO and GSH, and a significant attenuation of the increase in PGE2 and lipid peroxides induced by indomethacin. In contrast, L-NAME was found to exacerbate mucosal damage. In conclusion, the present study provides further evidence for the role of NO in gastric ulcer healing and it suggests an alternative path to treating the universal problem of non-steroidal anti-inflammatory-drug-induced gastropathy.

PREVENTION OF CISPLATIN-INDUCED NEPHROTOXICITY BY METHIMAZOLE.

Nephrotoxicity is a dose-limiting factor in the use of cisplatin against solid tumours. Methimazole, an antithyroid drug containing a free SH group, has a nephroprotective potential against chemically-induced nephrotoxicity. We tried to explore the nephrotoxic effect of the experimentally therapeutic dose of cisplatin (7 mg kg(-1), i.p.), particularly on the nuclear level of kidney cells in male albino rats, as well as the possible protective effect of methimazole. Furthermore, the drug interaction regarding the oncolytic effect of cisplatin was examined in Ehrlich ascites carcinoma (EAC)-bearing mice. A single dose of cisplatin caused kidney damage, 6 days after injection, manifested by 219% increase in serum creatinine, 384% increase in blood urea nitrogen and 170% increase in kidney content of lipid peroxides. Kidney DNA showed clear fragmentations detected by gel electrophoresis. However, kidney reduced glutathione was unchanged at that time period. Histological examination of kidney confirmed the toxic effect of cisplatin. Methimazole (40 mg kg(-1), i.p., 30 min before cisplatin injection) significantly protected the kidney from the nephrotoxic effect of cisplatin as judged from the biochemical parameters investigated as well as the histopathological examination. On the other hand, the survival data in EAC-bearing mice treated with both drugs indicated the persistence of an effective cytotoxic action. This study points to a promising use of this combination and necessitates further experimental and clinical studies. 2000 Academic Press@p$hr Copyright 2000 Academic Press.

Prevention of cisplatin-induced nephrotoxicity by methimazole.

Nephrotoxicity is a dose-limiting factor in the use of cisplatin against solid tumours. Methimazole, an antithyroid drug containing a free SH group, has a nephroprotective potential against chemically-induced nephrotoxicity. We tried to explore the nephrotoxic effect of the experimentally therapeutic dose of cisplatin (7 mg kg(-1), i.p.), particularly on the nuclear level of kidney cells in male albino rats, as well as the possible protective effect of methimazole. Furthermore, the drug interaction regarding the oncolytic effect of cisplatin was examined in Ehrlich ascites carcinoma (EAC)-bearing mice. A single dose of cisplatin caused kidney damage, 6 days after injection, manifested by 219% increase in serum creatinine, 384% increase in blood urea nitrogen and 170% increase in kidney content of lipid peroxides. Kidney DNA showed clear fragmentations detected by gel electrophoresis. However, kidney reduced glutathione was unchanged at that time period. Histological examination of kidney confirmed the toxic effect of cisplatin. Methimazole (40 mg kg(-1), i.p., 30 min before cisplatin injection) significantly protected the kidney from the nephrotoxic effect of cisplatin as judged from the biochemical parameters investigated as well as the histopathological examination. On the other hand, the survival data in EAC-bearing mice treated with both drugs indicated the persistence of an effective cytotoxic action. This study points to a promising use of this combination and necessitates further experimental and clinical studies.