Cyclophosphamide (CP) is a chemotherapeutic agent which is extensively used in the treatment of multiple neoplastic and nonneoplastic diseases like breast cancer, lymphomas, systemic lupus erythematosus, and multiple sclerosis. Dose‐limiting side effects, mainly nephrotoxicity is a major problem hindering its use in the clinical practice. CP induces nephrogenic syndrome of inappropriate antidiuresis mostly via the activation of arginine vasopressin V 2 receptors. Moreover, CP produces reactive metabolites which is responsible for augmentation of lipid peroxidation and oxidative stress. Tolvaptan (TOL) is a selective vasopressin V 2 receptor antagonist used in the treatment of clinically significant hyponatremia, volume overload in heart failure, and liver cirrhosis with edema. The present study aimed to investigate the potential protective effect of TOL in CP‐induced nephrotoxicity. Twenty‐four adult male albino rats were randomly divided into four groups: the control group, TOL group that treated daily with tolvaptan (10 mg/kg/d, orally), CP group where CP was administered intraperitoneally 75 mg/kg on days 3, 4, 5, 19, 20, and 21 of study, and the CP + TOL group where animals were treated with TOL daily with (10 mg/kg/d, orally) for 22 days with concomitant administration of CP as described before. Coadministration of TOL with CP induces significant improvement in the level of urine volume, serum Na+, serum osmolarity, urinary creatinine, and free water clearance in addition to significant reduction of body weight, serum creatinine, urea, serum K+, blood pressure, urine osmolarity, and the fractional excretion of sodium as compared to CP‐treated group. In addition, coadministration of TOL significantly reduced MDA, the marker of lipid peroxidation, and different pro‐inflammatory cytokines. Histopathological changes showed improvement in the signs of nephrotoxicity with the coadministration of TOL. Also, co‐treatment with TOL significantly decreased the level of markers of apoptosis as caspase‐3 and Bax with increased expression of antiapoptotic Bcl‐2 in renal tissue as compared to CP‐treated group.

The usefulness of cyclophosphamide (CP) in the treatment of multiple human malignancies and immunological diseases is hindered by the danger of developing nephrotoxicity. The toxic metabolites of CP are suggested to be responsible for oxidative stress resulted from the production of reactive oxygen species (ROS) and stimulation of lipid peroxidation. Nebivolol (NEB) is a third‐generation selective B1 adrenoceptor antagonist, but it has also various pharmacological properties such as anti‐inflammation, anti‐apoptotic, and antioxidant activities. Thus, the present study aims to explore the potential protective effect of NEB against CP‐induced nephrotoxicity. A cumulative dose of CP (75 mg/kg) was administered to albino rats by intraperitoneal injection. The protective effect of NEB was investigated by co‐administration of NEB (10 mg/kg orally daily). Administration of NEB with CP significantly improved renal functions and reduced the oxidative renal changes induced by CP injection. Co‐administration of NEB ameliorated apoptosis and inflammatory markers that were markedly exaggerated by CP. Our results indicated that NEB could be used as a protective agent against CP‐induced nephrotoxicity.

For clinicians, Pseudomonas aeruginosa is a nightmare pathogen that is one of the top three causes of opportunistic human infections. Therapy of P. aeruginosa infections is complicated due to its natural high intrinsic resistance to antibiotics. Active efflux and decreased uptake of drugs due to cell wall/membrane permeability appear to be important issues in the acquired antibiotic tolerance mechanisms. Bacterial cell wall biosynthesis enzymes have been shown to be essential for pathogenicity of Gram-negative bacteria. However, the role of these targets in virulence has not been identified in P. aeruginosa. Here, we report knockout (k.o) mutants of six cell wall biosynthesis targets (murA, PA4450; murD, PA4414; murF, PA4416; ppiB, PA1793; rmlA, PA5163; waaA, PA4988) in P. aeruginosa PAO1, and characterized these in order to find out whether these genes and their products contribute to pathogenicity and virulence of P. aeruginosa. Except waaA k.o, deletion of cell wall biosynthesis targets significantly reduced growth rate in minimal medium compared to the parent strain. The k.o mutants showed exciting changes in cell morphology and colonial architectures. Remarkably, ΔmurF cells became grossly enlarged. Moreover, the mutants were also attenuated in vivo in a mouse infection model except ΔmurF and ΔwaaA and proved to be more sensitive to macrophage-mediated killing than the wild-type strain. Interestingly, the deletion of the murA gene resulted in loss of virulence activity in mice, and the virulence was restored in a plant model by unknown mechanism. This study demonstrates that cell wall targets contribute significantly to intracellular survival, in vivo growth, and pathogenesis of P. aeruginosa. In conclusion, these findings establish a link between cell wall targets and virulence of P. aeruginosa and thus may lead to development of novel drugs for the treatment of P. aeruginosa infection.