Glucose-6-phosphate dehydrogenase inhibition attenuates acute lung injury through reduction in NADPH oxidase-derived reactive oxygen species.

Acute lung injury (ALI) is a heterogeneous disease with the hallmarks of alveolar capillary membrane injury, increased pulmonary oedema and pulmonary inflammation. The most common direct aetiological factor for ALI is usually parenchymal lung infection or haemorrhage. Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) are thought to play an important role in the pathophysiology of ALI. Glucose-6-phosphate dehydrogenase (G6PD) plays an important role both in production of ROS as well as their removal through the supply of NADPH. However, how G6PD modulation affects NOX2-mediated ROS in the airway epithelial cells (AECs) during acute lung injury has not been explored previously. Therefore, we investigated the effect of G6PD inhibitor, 6-aminonicotinamide on G6PD activity, NOX2 expression, ROS production and enzymatic anti-oxidants in AECs in a mouse model of ALI induced by lipopolysaccharide (LPS). ALI led to increased G6PD activity in the AECs with concomitant elevation of NOX2, ROS, SOD1 and nitrotyrosine. G6PD inhibitor led to reduction of LPS-induced airway inflammation, bronchoalveolar lavage fluid protein concentration as well as NOX2-derived ROS and subsequent oxidative stress. Conversely, ALI led to decreased glutathione reductase activity in AECs, which was normalized by G6PD inhibitor. These data show that activation of G6PD is associated with enhancement of oxidative inflammation in during ALI. Therefore, inhibition of G6PD might be a beneficial strategy during ALI to limit oxidative damage and ameliorate airway inflammation.

Salubrious effects of dexrazoxane against teniposide-induced DNA damage and programmed cell death in murine marrow cells.

The intention of the present study was to answer the question whether the catalytic topoisomerase-II inhibitor, dexrazoxane, can be used as a modulator of teniposide-induced DNA damage and programmed cell death (apoptosis) in the bone marrow cells in vivo. The alkaline single cell gel electrophoresis, scoring of chromosomal aberrations, micronuclei and mitotic activity were undertaken in the current study as markers of DNA damage. Apoptosis was analysed by the occurrence of a hypodiploid DNA peak and caspase-3 activity. Oxidative stress marker such as intracellular reactive oxygen species production, lipid peroxidation, reduced and oxidised glutathione were assessed in bone marrow as a possible mechanism underlying this amelioration. Dexrazoxane was neither genotoxic nor apoptogenic in mice at the tested dose. Moreover, for the first time, it has been shown that dexrazoxane affords significant protection against teniposide-induced DNA damage and apoptosis in the bone marrow cells in vivo and effectively suppresses the apoptotic signalling triggered by teniposide. Teniposide induced marked biochemical alterations characteristic of oxidative stress including accumulation of intracellular reactive oxygen species, enhanced lipid peroxidation, accumulation of oxidised glutathione and reduction in the reduced glutathione level. Prior administration of dexrazoxane ahead of teniposide challenge ameliorated these biochemical alterations. It is thus concluded that pretreatment with dexrazoxane attenuates teniposide-induced oxidative stress and subsequent DNA damage and apoptosis in bone marrow cells. Based on our data presented, strategies can be developed to decrease the teniposide-induced DNA damage in normal cells using dexrazoxane. Therefore, dexrazoxane can be a good candidate to decrease the deleterious effects of teniposide in the bone marrow cells of cancer patients treated with teniposide.

Boric acid enhances in vivo Ehrlich ascites carcinoma cell proliferation in Swiss albino mice.

The influence of boric acid, a boron carrier, on Ehrlich ascites carcinoma (EAC) cell-bearing mice was investigated in view of its importance in the boron neutron capture therapy and the influence of boron on proliferation and progression of cancer cells mediated by proteoglycans and collagen. The present study included the evaluation of boric acid for the effects on total count and viability of EAC cells in addition to their non-protein sulfhydryls (NP-SH) and malondialdehyde (MDA) contents as parameters for conjugative detoxication potency and possible oxidative damage. The EAC cell-bearing animals were also observed for the effect on survival, body weight changes, and histopathological evaluation of the tumors grown at the site of inoculation. The treatment with boric acid significantly increased the total number of peritoneal EAC cells and their viability. A significant increase in the body weight was observed that dose-dependently reached plateau levels by 20 days of treatment. Conversely, a reduction in the duration of survival of these animals was evident with the same protocol. Boric acid treatment resulted in a decrease in NP-SH contents with a concomitant increase in MDA levels in EAC cells as revealed by the results of the biochemical analysis. These data are supported by our results on histopathological investigations, which apparently showed fast growth, in addition to several mitotic figures and mixed inflammatory reaction, after treatment with boric acid. It seems likely that a particular combination of properties of boric acid, rather than a single characteristic alone, will provide useful information on the use of this boron carrier in neutron capture therapy.

Effect of ninhydrin on the biochemical and histopathological changes induced by ethanol in gastric mucosa of rats.

Studies on the effect of ninhydrin in the normal gastric mucosa and against the ethanol induced gastric injury were undertaken in rats in view of the presence of a carbonyl function as well as hydroxyl groups in its chemical structure. In spite of its potentials to generate hydroxyl radicals, it is deemed to possess antioxidant property by virtue of its electrophilic nature. Recent studies have shown gastro-protection to mediate through a reaction between the electrophilic compounds and sulfhydryl groups of the mucosa. Hence it was found worthwhile to evaluate the interaction between the oxidant and antioxidant functions in the structure of the same compound. The effects of ninhydrin pretreatment on gastric mucosal injuries caused by 80% ethanol, 25% NaCl and 0.2M NaOH were investigated in rats. The gastric tissue in ethanol-treated rats was analyzed for different histopathological lesions. In addition, the effects on ethanol-induced changes in the gastric levels of proteins, nucleic acids, non-protein sulfhydryl (NP-SH) and malondialdehyde (MDA) were also evaluated. Ninhydrin, as such, failed to induce any significant changes in normal gastric mucosa, while its pretreatment at oral doses of 5, 10 and 20 mg/kg was found to provide a dose-dependent protection against the ulcers induced by ethanol, NaOH and NaCl. The results of histopathological evaluation revealed a protective effect of ninhydrin on congestion, hemorrhage, edema, erosions and necrosis caused by ethanol. Furthermore, the pretreatment afforded a dose-dependent inhibition of the ethanol-induced depletion of proteins, nucleic acids, NP-SH and increase of MDA in the gastric tissue. The results obtained clearly demonstrate the anti-ulcerogenic activity of ninhydrin. The exact mechanism of action is not known. However, the carbonyl function in ninhydrin appears to achieve antioxidant balance and protect the gastric mucosa from the ethanol-induced gastric injury. Further studies are warranted to investigate the toxicity and detailed mechanism of action of this potent compound before any clinical trials, especially at the effective lower doses.

Inhibition of gastric mucosal damage by methylglyoxal pretreatment in rats.

The effect of methylglyoxal pretreatment on gastric mucosal injuries caused by 80% ethanol, 25% NaCl and 0.2 M NaOH, was investigated in rats. The effects caused by pylorous ligation accumulated gastric acid secretions and ethanol-induced changes in gastric mucus secretions, levels of proteins, nucleic acid, malondialdehyde (MDA) and non-protein sulfhydryl groups were also investigated. Methylglyoxal pretreatment at oral doses of 50, 100 and 200 mg/kg body weight was found to provide a dose-dependent protection against the ulcerogenic effects of different necrotizing agents used. With the same dose regimen methylglyoxal offered significant protection against ethanol-induced damage on the parameters evaluated for histopathology. Furthermore, the pretreatment afforded a dose-dependent inhibition of pylorous ligated accumulation of gastric acid secretions and ethanol-induced depletion of stomach wall mucus, proteins, nucleic acids, NP-SH contents and an increase in the MDA levels in gastric tissue. The protective effect of methylglyoxal against ethanol-induced damage to the gastric wall mucosa may be mediated through its effect on mucous production, proteins, nucleic acids, NP-SH groups and its free-radical scavenging property under the influence of polyamines stimulated by ornithine decarboxylase activity (ODC).

Studies on the cytotoxic, biochemical and anti-carcinogenic potentials of ninhydrin on Ehrlich ascites carcinoma cell-bearing Swiss albino mice.

Ninhydrin (2,2-dihydroxy-1,3-indane dione) was evaluated for its antitumor and cytotoxic properties in Ehrlich ascites carcinoma cell (EAC Cell)-bearing mice. The rationale behind this study has been mainly the literature reports of its characteristic interference with DNA synthesis and calcium homeostasis. Antitumor activity was evaluated from the total count and viability of EAC cells in addition to their nucleic acid, protein, non-protein sulfhydryls (NP-SH) and malondialdehyde (MDA) contents. The EAC cell-bearing animals were also observed for the effect on their survival and body weight variations. In addition, the tumors grown at the site of injection were evaluated for histopathological changes. Ninhydrin treatments (5, 10 and 20 mg/kg/day) abate the increase in body weight and advanced the duration of survival in EAC cell-bearing mice. The results on histopathological investigations show retardation in tumor growth, decreased frequency of mitotic figures and hair follicles and an increased necrosis in the tumor by ninhydrin treatment. Our results on cytotoxicity, which demonstrated compression in the number of EAC cells and their viability substantiate these data. The results of biochemical studies on EAC cells exhibit a reduction in the levels of DNA, RNA, proteins and NP-SH with a subsequent increase in the concentrations of MDA after ninhydrin treatment. Inhibition in tumor growth was dose dependently significant with the same dose regimen. The observed cytotoxic and antitumor activity of ninhydrin was comparable to cyclophosphamide. The possible mode of action of ninhydrin-induced cytotoxic and antitumor activity appear to be due to its interference with mitochondrial function resulting in inhibition of DNA synthesis, an effect that is being investigated further.

Gastric antiulcer and cytoprotective effect of Commiphora molmol in rats.

The aqueous suspension of Commiphora molmol (oleo-gum resin) has been screened for its potential to protect gastric mucosa against the ulcers caused by 80% ethanol, 25% NaCl, 0.2 M NaOH, indomethacin and combined indomethacin-ethanol treatment. C. molmol pretreatment at doses of 250, 500 and 1000 mg/kg provided dose-dependent protection against the ulcerogenic effects of different necrotizing agents used. The effects caused by ethanol were further investigated. Treatment of rats with 1 ml of 80% ethanol was found to cause depletion of stomach wall mucus, reduction in the concentration of protein, nucleic acids and NP-SH groups in the stomach wall. Ethanol treatment also caused histopathological lesions including necrosis, erosion, congestion and haemorrhage of the stomach wall. Pretreatment with C. molmol offered a dose-dependent protection against all these effects. In the same manner it affected the malondialdehyde concentration altered by ethanol treatment. C. molmol also offered protection against mucosal damage caused by indomethacin and its combination with ethanol. The protective effect of C. molmol observed in the present study is attributed to its effect on mucus production, increase in nucleic acid and non-protein sulfhydryl concentration, which appears to be mediated through its free radical-scavenging, thyroid-stimulating and prostaglandin-inducing properties.

Effect of camel urine on the cytological and biochemical changes induced by cyclophosphamide in mice.

Camel urine treatment was found to cause a significant cytotoxic effect in the bone marrow cells of mice. This cytotoxicity at higher doses was comparable with that of standard drug cyclophosphamide (CP). However, unlike CP, the camel urine treatment failed to induce any clastogenicity. The cytotoxicity induced by camel urine treatment was substantiated by the reduction of liver nucleic acids and glutathione levels and increased malondialdehyde (MDA) contents in the same animals. CP treatment was found to be highly clastogenic, cytotoxic and it reduced the levels of nucleic acids, proteins, glutathione and increased malondialdehyde concentration due to its prooxidant nature. The non-clastogenic nature of camel urine was attributed to the antioxidant and antimutagenic compounds present in camel urine. Pretreatment with camel urine increased the cytotoxicity of CP and intensified the CP induced reduction of liver nucleic acids, glutathione and increased the MDA concentration. The increase of CP induced cytotoxicity appears to be partly due to the additive effect of the two treatments on cellular lipid peroxidation.

Effect of desferrioxamine on cisplatin-induced nephrotoxicity in normal rats.

Biochemical and histological evaluations of the effects of the iron chelator desferrioxamine on the nephrotoxicity induced by cisplatin in normal rats were carried out. A single dose of cisplatin (7.5 mg/kg, intravenously) caused nephrotoxicity that manifested biochemically as an elevation of blood urea nitrogen, serum creatinine and an increase in the kidney weight as a percent of body weight. Moreover, severe decreases in serum calcium and albumin were observed. Histopathological examination of kidney tissue revealed tubular necrosis with sloughing of tubular epithelium. Desferrioxamine treatment (250 mg/kg, intraperitoneally) 30 min before cisplatin administration does not protect the kidney from the damaging effects of cisplatin. A greater increase in blood urea nitrogen, serum creatinine and kidney weight was observed with significant tubular necrosis and a mild lymphocytic infiltrate. Desferrioxamine pretreatment decreased the lipid peroxidation induced by cisplatin but at the same time increased nonprotein sulfhydryl (-SH) concentrations in the kidney tissue. The findings of this study suggest that lipid peroxidation is not the main cause of cisplatin-induced nephrotoxicity and that desferrioxamine which was useful for prevention of cardiac and hematological damage induced by doxorubicin, aggrevated the cisplatin-induced nephrotoxicity. More investigations are needed to establish a definite assessment of its selectivity.

Diltiazem potentiation of doxorubicin cytotoxicity and cellular uptake in Ehrlich ascites carcinoma cells.

The calcium channel blocker diltiazem, which possesses coronary vasodilator activity, greatly enhanced the cytotoxicity of doxorubicin in Ehrlich ascites carcinoma cells. 20% of the doxorubicin-treated tumor-bearing animals (2 mg/kg, every other day, three doses) survived, with a mean survival time of 35 days. However, pretreatment with diltiazem increased survival to 70% with a mean survival time of 43 days. Diltiazem treatment increased the intracellular level of doxorubicin, and there was a good correlation between the high cellular level of doxorubicin and its cytotoxic activity. In tumor-bearing animals pretreated with diltiazem, doxorubicin showed a pronounced inhibitory effect on cellular DNA, RNA content and acid phosphatase activity of tumor cells. In addition, there was a marked increase in cellular cholesterol and lipid contents. This study may suggest the benefit of using diltiazem to potentiate the cytotoxic effect of doxorubicin, allowing its dose and consequently the serious side effects to be reduced.

Influence of anethole treatment on the tumour induced by Ehrlich ascites carcinoma cells in paw of Swiss albino mice.

The anticarcinogenic potential of anethole was studied in Ehrlich ascites tumour (EAT) in the paw of Swiss albino mice. The antitumour activity was evaluated from the cytotoxicity of EAT-cells in the paw and their biochemical changes were determined from nucleic acids, protein, malondialdehyde (MDA) and glutathione (NP-SH) concentrations. Furthermore, the observations on survival rate, tumour weight, its volume and body weight of EAT-bearing mice were made. The EAT-bearing paws were also evaluated for histopathological changes. Additional studies were undertaken on the cytological effects of anethole in order to establish its clastogenic and mitodepressive activity in normal mice. The results obtained in the present study revealed anethole to increase the survival time, reduce the tumour weight and volume and body weight of the EAT-bearing mice. It caused a significant cytotoxic effect in EAT cells in the paw, reduced the levels of nucleic acids and MDA, and increased NP-SH concentrations. The histopathological changes observed after treatment with anethole were comparable to the standard cytotoxic drug cyclophosphamide. The results on the frequency of micronuclei and the ratio of polychromatic erythrocytes to normochromatic erythrocytes showed anethole to be mitodepressive and non-clastogenic in the femoral cells of mice. Our results indicate the anticarcinogenic, cytotoxic and non=clastogenic nature of anethole. Further studies are warranted to explore the mode of action and safety of anethole for its possible use in cancer therapy.

Effect of acute administration of fish oil (omega-3 marine triglyceride) on gastric ulceration and secretion induced by various ulcerogenic and necrotizing agents in rats.

The fish oil commercially known as Marine-25 (omega-3 marine triglyceride) is an eicosapentaenoic acid (EPA)-rich oil. It was investigated for its ability to inhibit gastric secretion and to protect the gastric mucosa against the injuries caused by pyloric ligation, non-steroidal anti-inflammatory drugs (NSAIDs--aspirin and indomethacin), reserpine, hypothermic restraint stress and necrotizing agents [0.6 M HCl 0.2 M NaOH or 80% (v/v) aqueous ethanol]. The results showed that the fish oil, at a dose of 5 or 10 ml/kg body weight, provided significant protection in the various experimental models used. It produced a significant inhibition of gastric mucosal damage induced by pyloric ligation, NSAIDs, reserpine or hypothermic restraint ulcers. Fish oil also exerted a significant inhibitory action on gastric mucosal lesions produced by various necrotizing agents. Our findings show that fish oil rich in eicosapentaenoic acid possesses both antisecretory and antiulcerogenic effects.

Anticarcinogenic effect of Commiphora molmol on solid tumors induced by Ehrlich carcinoma cells in mice.

The anticarcinogenic potential of Commiphora molmol (oleoresin) was studied in Ehrlich-solid-tumor-bearing mice. The antitumor activity of C. molmol was evaluated from the total count and viability of Ehrlich solid tumor cells and their nucleic acid, protein, malondialdehyde and glutathione levels at the end of 25 and 50 days of treatment. Furthermore, observations of animal survival rate and measurements of the tumor and body weight were made. The Ehrlich solid tumors were also evaluated for histopathological changes. Treatment with C. molmol (250 and 500 mg/kg/day) was found to be cytotoxic in Ehrlich solid tumors cells. The antitumor potential of C. molmol was comparable to the standard cytotoxic drug cyclophosphamide. This effect of C. molmol was less pronounced after 50 days of treatment. The present study confirmed the cytotoxic and anticarcinogenic potential of C. molmol. Further studies are warranted to explore its mode of action and safety for medicinal use in cancer therapy.

Evaluation of Caralluma tuberculata pretreatment for the protection of rat gastric mucosa against toxic damage.

The ethanolic extract of Caralluma tuberculata N. E. Brown has been screened for its potential to protect gastric mucosa against the injuries caused by 80% ethanol, 0.2 M NaOH, hypertonic saline, and indomethacin. C. tuberculata at doses of 250, 500, and 1000 mg/kg body wt given 30 min before the necrotizing agents provided dose-dependent protection against the damage caused by all tested agents. The effects caused by ethanol were further investigated. Treatment of rats with 1 ml of 80% ethanol (gavage) was found to cause depletion of stomach-wall mucus, to lower the concentrations of proteins, nucleic acids, and nonprotein sulfhydryl groups in the stomach wall, and to cause histopathological lesions, including necrosis, erosions, congestion, and hemorrhage, of the stomach wall. C. tuberculata treatment caused a dose-dependent protection against all these effects. In the same manner it affected malondialdehyde concentrations altered by ethanol treatment. C. tuberculata also offered protection against mucosal damage caused by indomethacin. The protective effects of C. tuberculata in addition to its effects on mucus production and nonprotein sulfhydryl concentration may be mediated through its free radical scavenging and prostaglandin inducing properties.

Enhancement of doxorubicin-induced cytotoxicity by hyperthermia in Ehrlich ascites cells.

Hyperthermia (HPT) at 43 degrees C for 30 min increased the cytotoxic activity of doxorubicin against the growth of Ehrlich ascites carcinoma cells. There was more delay in tumor growth with 89% inhibition in the tumor volume and 90% increase in the survival of the tumor-bearing animals compared to control group. Combination of HPT with doxorubicin showed a more pronounced inhibitory effect on tumor content of DNA, RNA, protein, cholesterol, total lipid and acid phosphatase activity. HPT did not significantly affect the doxorubicin uptake into tumor cells, but it has some inhibitory effect on some vital components. Along with other results, our data suggest the benefit of using HPT to enhance the cytotoxic activity of doxorubicin with a consequent reduction of doxorubicin dose and hence a decrease of its serious side effects.

Studies on the antiinflammatory, antipyretic and analgesic activities of santonin.

Santonin, a sesquiterpene lactone, commonly found in the plants of the family Compositae was found to show significant antiinflammatory activity on acute inflammatory processes. The activity profile of santonin closely resembled that of a standard non-steroidal antiinflammatory drug, diclofenac sodium. It also showed a significant inhibitory effect on granuloma formation; however, this effect of santonin was less pronounced as compared to diclofenac sodium. Santonin caused a significant antipyretic effect in mice, which was found to be independent of the route of administration of the drug. It also increased the hot plate reaction time of treated mice, similar to morphine.

Effect of Commiphora molmol (oleo-gum-resin) on the cytological and biochemical changes induced by cyclophosphamide in mice.

The anticlastogenic and biochemical potentials of Commiphora molmol were studied in Swiss albino mice treated with cyclophosphamide (CP). The C.molmol treatment (125-500 mg/kg) showed no mutagenicity. It caused a highly significant and dose-dependent mitodepressant effect in the femoral cells and reduction of RNA levels in hepatic cells as compared with the control. CP treatment showed significant increase in the frequency of micronuclei, cytotoxicity and reduction in the contents of nucleic acids and proteins. Pretreatment with C. molmol could neither alter the biochemical and cytological effects of CP nor show any additive effect of both treatments.

Evaluation of teratogenic potential of khat (Catha edulis Forsk.) in rats.

The embryotoxic and teratogenic effects of khat (Catha edulis Forsk.), a plant chewed by the people of Eastern Africa and Southern Arabia to attain a state of euphoria and stimulation, was studied in Wistar rats. Methanolic extract of khat was administered orally by gavage to rats during days from 6 to 15 of gestation at doses of 0, 125, 250 and 500 mg/kg. body weight/day. Khat reduced the food consumption and maternal weight gain and also lowered the food efficiency index, as compared to control mothers. On day 20 of gestation, all dams were sacrificed by cervical dislocation, cesarean sections were performed and maternal and fetal toxicities were assessed. The administration of khat had no effect on fetal sex ratio. However, at a dose of 125 mg/kg body weight and above, it produced a significant increase in resorptions and fetal wastage. Khat administration in utero also reduced the litter size and caused intrauterine growth retardation. External, visceral and skeletal examination of the fetus of treated dams showed several types of malformations and variations in all the groups of animals. However, a consistent tendency of abnormalities was observed in the highest dosed (500 mg/kg) group. The data of the present study revealed that khat retarded fetal growth and induced terata. The present observations indicate that khat possesses both embryotoxic as well as teratogenic properties. The developmental toxicities of khat are dose-related.

Potentiation of doxorubicin cytotoxicity by the calcium channel blocker verapamil in Ehrlich ascites cells.

The calcium channel blocker verapamil increased the intracellular level of doxorubicin in Ehrlich ascites cells. The high cellular drug level was directly related to the enhancement of the cytotoxicity of the antitumor agent. Tumor-bearing mice pretreated with verapamil showed a 2.3-fold increase in long-term survival effect of doxorubicin together with a pronounced inhibitory effect on tumor DNA, RNA and protein content. This study suggests the possible novel use of verapamil to enhance the antitumor activity of doxorubicin, allowing its dose, and consequently the serious side effects, to be reduced.