Studies on cigarette smoke induced oxidative DNA damage and reduced spermatogenesis in rats.

In the present work, the effect of exposure to cigarette smoke on male fertility in rats, as characterized by changes in the relative weight of sex organs, epididymal sperm count, activity of marker enzymes and DNA damage was evaluated. Exposure of rats to cigarette smoke caused a gradual decrease in total body weight gain and relative weight of the epididymis and seminal vesicles by 30 and 40% respectively. Epididymal sperm count was reduced significantly by 25% (P 0.05) after 2 weeks and by 41% (P 0.001) after 4 weeks of exposure. Exposure to cigarette smoke had reduced the activity of sorbitol dehydogenase by 18% (P < or = 0.05) and increased the activity of lactate dehydrogenase by 28% (P < or = 0.05). The changes in both key enzymes were significant, which reflected the inhibitory effect of cigarette smoke on spermatogenesis and sperm maturation. The toxic effect of exposure could be explained partially due to induction of DNA damage and oxidative stress as shown by the significant increase in serum 8-hydroxy-2'-deoxyguanosine from 22.83 to 37.33 ng ml(-1) blood.

The antioxidant activity of copper(II) (3,5-diisopropyl salicylate)4 and its protective effect against streptozotocin-induced diabetes mellitus in rats.

Oxidative stress has been suggested as a potential contributor to the development of diabetic complications. In this study, we investigated the protective effect of a strong antioxidant copper complex against streptozotocin (STZ)-induced diabetes in animals. Out of four copper complexes used, copper(II) (3,5-diisopropyl salicylate)4 (Cu(II)DIPS) was found to be the most potent antioxidant-copper complex. Pretreatment with Cu(II)DIPS (5 mg/kg) twice a week prior to the injection of streptozotocin (50 mg/kg) has reduced the level of hyperglycemia by 34 % and the mortality rate by 29 %. Injection of the same dosage of the ligand 3,5-diisopropyl salicylate has no effect on streptozotocin-induced hyperglycemia. The same copper complex has neither hypoglycemic activity when injected in normal rats nor antidiabetic activity when injected in STZ-induced diabetic rats. The protective effect of Cu(II)DIPS could be related to its strong antioxidant activity compared to other copper complexes median effective concentration (MEC) = 23.84 µg/ml and to Trolox MEC = 29.30 µg/ml. In addition, it reduced serum 8-hydroxy-2'-deoxyguanosine, a biomarker of oxidative DNA damage, by 29 %. This effect may explain why it was not effective against diabetic rats, when ß Langerhans cells were already destroyed. Similar protective activities were reported by other antioxidants like Trolox.

The teratogenicity and behavioral teratogenicity of di(2-ethylhexyl) phthalate (DEHP) and di-butyl phthalate (DBP) in a chick model.

Phthalates are industrial chemicals widely used in consumer products, plastics and children toys, and the risk of exposure to phthalates, especially prenatal exposure, is a growing concern justifying the development of an animal model to better understand their effect. The present study was designed to evaluate the suitability of a chick model for phthalate DEHP teratogenicity and neurobehavioral teratogenicity, a model which is simple and devoid of potential confounding factors such as maternal toxicity, maternal-fetal unit and maternal-neonatal interactions; major findings were confirmed in the DBP study. Prehatch exposure to DEHP in doses ranging from 20 to 100 mg/kg, reduced the percent hatching from 80% in control eggs to 65%, and increased late hatchings from 12.5% in control eggs to 29.4%. In addition it induced developmental defects characterized by an opening or weakening of abdominal muscles allowing internal organs to protrude externally with or without a sac, omphalocele or gastroschisis, respectively. The effect was dose dependent ranging from 8% with DEHP (20 mg/kg) to 22% (100 mg/kg). Similar treatment with DBP 100mg/kg has reduced percentage hatching to 57% and increased late hatching to 37.5%, with a 14% increase in gastroschisis. Biochemical evaluation revealed elevated levels of alkaline phosphatase, which reflects non-specific toxicity of DEHP at such a high dose. Behavioral evaluation using an imprinting test and locomotor activity on chicks pretreated with DEHP (100 mg/kg) has shown an abolishment of imprinting performance from the control (0.65) preference ratio. DNA damage measurements of the metabolite 8-hydroxydeoxyguanosine (8-OH-dG) in blood samples showed an increase of 39.7% after prehatch exposure to phthalates. This was statistically significant for DEHP and indicates genetic toxicity, since part of the teratogenic activity is associated with oxidative stress and DNA damage.

Effect of Palestinian honey on spermatogenesis in rats.

Treatment of male albino rats with 5% honey for 20 days had no significant effect on total body weight or on the relative weight of other organs like the testis, seminal vesicles, spleen, kidneys, liver, heart, or brain. The only significant change was a 17% increase in the relative weight of the epididymis (P < or = .01). The relative weight of all the other organs was similar to those in control animals treated for the same period with drinking water. Treatment of rats for the same period with the same concentration of 5% sucrose produced no significant changes in absolute or relative weight of tested organs compared to control animals. The same treatment with Palestinian honey increased significantly the epididymal sperm count by 37% (P < or = .05). The activity of testicular marker enzymes for spermatogenesis such as sorbitol dehydrogenase (SDH) was increased by 31% (P < or = .05), and lactate dehydrogenase (LDH) was reduced by 48% (P < or = .05), which indicates that treatment with honey induces spermatogenesis. Similar treatment with sucrose had no significant effect on any of the key enzymes or epididymal sperm count. In conclusion, our results show that ingestion of honey induces spermatogenesis in rats by increasing epididymal sperm count, increasing selectively the relative weight of the epididymis, and increasing SDH activity and reducing LDH activity.

Prediction of doxorubicin sensitivity in breast tumors based on gene expression profiles of drug-resistant cell lines correlates with patient survival.

Up to date clinical tests for predicting cancer chemotherapy response are not available and individual markers have shown little predictive value. We hypothesized that gene expression patterns attributable to chemotherapy-resistant cells can predict response and cancer prognosis. We contrasted the expression profiles of 13 different human tumor cell lines of gastric (EPG85-257), pancreatic (EPP85-181), colon (HT29) and breast (MCF7 and MDA-MB-231) origin and their counterparts resistant to the topoisomerase inhibitors daunorubicin, doxorubicin or mitoxantrone. We interrogated cDNA arrays with 43 000 cDNA clones ( approximately 30 000 unique genes) to study the expression pattern of these cell lines. We divided gene expression profiles into two sets: we compared the expression patterns of the daunorubicin/doxorubicin-resistant cell lines and the mitoxantrone-resistant cell lines independently to the parental cell lines. For identifying predictive genes, the Prediction Analysis for Mircorarrays algorithm was used. The analysis revealed 79 genes best correlated with doxorubicin resistance and 70 genes with mitoxantrone resistance. In an independent classification experiment, we applied our model of resistance for predicting the sensitivity of 44 previously characterized breast cancer samples. The patient group characterized by the gene expression profile similar to those of doxorubicin-sensitive cell lines exhibited longer survival (49.7+/-26.1 months, n=21, P=0.034) than the resistant group (32.9+/-18.7 months, n=23). The application of gene expression signatures derived from doxorubicin-resistant and -sensitive cell lines allowed to predict effectively clinical survival after doxorubicin monotherapy. Our approach demonstrates the significance of in vitro experiments in the development of new strategies for cancer response prediction.

Gene expression in the bladder carcinoma rat model.

We investigated gene expression in N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN)-induced rat bladder carcinoma in order to test its applicability as a model for the study of novel therapeutic modalities, particularly gene therapy. We administered BBN in the drinking water to Wistar rats for up to 30 wk and induced papillary transitional cell carcinoma (TCC), which is similar to the most prevalent type of human bladder cancer. Tumor evolution was similar to that found in previous studies. However, we described the morphological stages according to modern human bladder carcinoma terminology. Our main goal was to examine the expression levels of the H19 gene, of the insulin-like growth factor 2 (Igf2) transcripts expressed from promoters P2 and P3 and of the telomerase subunits that we had previously investigated as tools for targeted gene therapy of bladder cancer. We detected at 30 wk of BBN exposure significant upregulation of these sequences in the rat bladder tumors, similar to our previous findings in human bladder cancer. To reinforce the similarity of this model to the corresponding human disease, we searched for additional tumor-specific genes documented as having altered expression in human bladder carcinoma, using cDNA expression arrays (Clontech). We suggest that BBN-induced rat bladder cancer has morphological, biological, and molecular parallels to human bladder cancer and is an attractive model for studying novel alternatives of therapeutic intervention.