The effects of Nigella sativa on bile duct ligation induced‐liver injury in rats

Nigella sativa (NS) has been shown to have antioxidant and antiinflammatory activities in different conditions. The goal of this study was to evaluate the effects of NS on cholestatic liver injury in rats. Thirty rats were recruited in the study as follows: Group 1, Bile duct ligation (BDL) (n = 10); Group 2, BDL plus NS (n = 10); and Group 3, Sham (n = 10). Bile duct ligated group received 0.2 mL kg^?1 dose of NS intraperitoneally daily throughout 14 days. Liver damage and cholestasis were determined by the biochemical and the pathologic examination. Data showed a decrease in gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) activities of the NS treated rats when compared with BDL group (p < 0.001 for GGT and p < 0.05 for others). The NS treated rats' tissue levels of total oxidant status (TOS), oxidative stress index (OSI), and myeloperoxidase (MPO) were significantly lower than that of the BDL group (p < 0.01 for all). Increases in total antioxidant capacity (TAC) and catalase (CAT) levels were statistically significant in the NS treated rats compared to BDL group (p < 0.01 for both). On the other hand, administration of NS in the rats with biliary obstruction resulted in inhibition of necro‐inflammation. These results indicate that NS exerts a therapeutic effect on cholestatic liver injury in bile duct ligated rats possibly through attenuation of enhanced neutrophil infiltration and oxidative stress in the liver tissue. Copyright © 2009 John Wiley & Sons, Ltd.     

Alterations of oxidative-antioxidative status in human cutaneous leishmaniasis

Enhanced lipid peroxidation and decreased antioxidant defences have been defined in several diseases. In the present study, we aimed to evaluate the oxidative-antioxidative status of patients with cutaneous leishmaniasis (CL). Concentrations of erythrocyte lipid peroxidation (LPO), as an indicator for the oxidative status, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and serum vitamin C levels, as indicators for the antioxidative status, were measured. Seventy patients aged between 15 and 50 years (38 patients had active CL and 32 patients had healed CL) and 40 healthy controls aged between 19 and 50 years were included in the study. LPO and GSH of the patients with active CL were significantly higher (p < 0.001), whereas erythrocyte GSH-Px and serum vitamin C levels were lower (p < 0.001, p < 0.01 respectively) than those of healthy controls. There was a significant inverse correlation between LPO and serum vitamin C level (r=-0.32, p < 0.05) in active CL. No significant correlation of LPO, GSH, GSH-Px and serum vitamin C levels in control groups or in the group with healed CL was detected. In the light of our findings it is possible to conclude that patients having CL are affected by oxidative stress, which most likely induces the endogenous antioxidant system. An imbalance between the oxidant and antioxidant systems occurs and the suppressed antioxidants and increased lipid peroxidation may contribute to the progression of the disease.     

Immune responses and parasite transmission in blood-feeding insects

The detailed model of insect immunity being built for Drosophila, allied to mass sequencing programs for blood-feeding insects, has led to advances in our understanding of the interaction between pathogens and insect vectors. An outline of insect immunity is given here based on the Drosophila studies, which is used as a framework to discuss recent work on Plasmodium-mosquito and Trypanosoma-tsetse interactions.     

The chemokine receptor CXCR3 and its splice variant are expressed in human airway epithelial cells

Activation of the chemokine receptor CXCR3 by its cognate ligands induces several differentiated cellular responses important to the growth and migration of a variety of hematopoietic and structural cells. In the human respiratory tract, human airway epithelial cells (HAEC) release the CXCR3 ligands Mig/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11. Simultaneous expression of CXCR3 by HAEC would have important implications for the processes of airway inflammation and repair. Accordingly, in the present study we sought to determine whether HAEC also express the classic CXCR3 chemokine receptor CXCR3-A and its splice variant CXCR3-B and hence may respond in autocrine fashion to its ligands. We found that cultured HAEC (16-HBE and tracheocytes) constitutively expressed CXCR3 mRNA and protein. CXCR3 mRNA levels assessed by expression array were approximately 35% of beta-actin expression. In contrast, CCR3, CCR4, CCR5, CCR8, and CX3CR1 were <5% beta-actin. Both CXCR3-A and -B were expressed. Furthermore, tracheocytes freshly harvested by bronchoscopy stained positively for CXCR3 by immunofluorescence microscopy, and 68% of cytokeratin-positive tracheocytes (i.e., the epithelial cell population) were positive for CXCR3 by flow cytometry. In 16-HBE cells, CXCR3 receptor density was approximately 78,000 receptors/cell when assessed by competitive displacement of 125I-labeled IP-10/CXCL10. Finally, CXCR3 ligands induced chemotactic responses and actin reorganization in 16-HBE cells. These findings indicate constitutive expression by HAEC of a functional CXC chemokine receptor, CXCR3. Our data suggest the possibility that autocrine activation of CXCR3 expressed by HAEC may contribute to airway inflammation and remodeling in obstructive lung disease by regulating HAEC migration.     

The major protein in the midgut of teneral Glossina morsitans morsitans is a molecular chaperone from the endosymbiotic bacterium Wigglesworthia glossinidia

Molecules in the midgut of the tsetse fly (Diptera: Glossinidiae) are thought to play an important role in the life cycle of African trypanosomes by influencing their initial establishment in the midgut and subsequent differentiation events that ultimately affect parasite transmission. It is thus important to determine the molecular composition of the tsetse midgut to aid in understanding disease transmission by these medically important insect vectors. Here, we report that the most abundant protein in the midguts of teneral (unfed) Glossina morsitans morsitans is a 60 kDa molecular chaperone of bacterial origin. Two species of symbiotic bacteria reside in the tsetse midgut, Sodalis glossinidius and Wigglesworthia glossinidia. To determine the exact origin of the 60 kDa molecule, a protein microchemical approach involving two-dimensional (2-D) gel electrophoresis and mass spectrometry was used. Peptide mass maps were compared to virtual peptide maps predicted for S. glossinidius and W. glossinidia 60 kDa chaperone sequences. Four signature peptides were identified, revealing that the source of the chaperone was W. glossinidia. Comparative 2-D gel electrophoresis and immunoblotting further revealed that this protein was localized to the bacteriome and not the distal portion of the tsetse midgut. The possible function of this highly abundant endosymbiont chaperone in the tsetse midgut is discussed.     

Effects of melatonin on oxidative-antioxidative status of tissues in streptozotocin-induced diabetic rats

In view of the antioxidant properties of melatonin, the effects of melatonin on the oxidative-antioxidative status of tissues affected by diabetes, e.g. liver, heart and kidneys, were investigated in streptozotocin (STZ)-induced diabetic rats in the present study. Concentrations of malondialdehyde (MDA) and reduced glutathione (GSH), and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the tissues were compared in three groups of 10 rats each (control non-diabetic rats (group I), untreated diabetic rats (group II) and diabetic rats treated with melatonin (group III)). In the study groups, diabetes developed 3 days after intraperitoneal (i.p.) administration of a single 60 mg kg(-1) dose of STZ. Thereafter, while the rats in group II received no treatment, the rats in group III began to receive a 10 mg kg(-1) i.p. dose of melatonin per day. After 6 weeks, the rats in groups II and III had significantly lower body weights and higher blood glucose levels than the rats in group I (p < 0.001 and p < 0.001, respectively). MDA levels in the liver, kidney and heart of group II rats were higher than that of the control group (p < 0.01, p < 0.05, p < 0.01, respectively) and diabetic rats treated with melatonin (p < 0.05). The GSH, GSH-Px and SOD levels increased in diabetic rats. Treatment with melatonin changed them to near control values. Our results confirm that diabetes increases oxidative stress in many organs such as liver, kidney and heart and indicate the role of melatonin in combating the oxidative stress via its free radical-scavenging and antioxidant properties.