Effects of WR-2721 and cyclophosphamide on the cell cycle phase specificity of apoptosis in mouse bone marrow

Candida glabrata colonizes but does not often disseminate from the mouse caecum

Candida glabrata is the second or third most frequent cause of candidaemia. The gastrointestinal tract is considered to be a major portal of entry for systemic candidiasis, but relatively few studies have investigated the pathogenesis of C. glabrata. Experiments were designed to clarify the ability of C. glabrata to disseminate from the mouse intestinal tract. Following oral inoculation, C. glabrata readily colonized the caeca [approx. 107 cells (g caecum)−1] of antibiotic-treated mice, but extraintestinal dissemination was not detected. Superimposing several mouse models of trauma and/or immunosuppression known to induce dissemination of Candida albicans and other intestinal microbes did not cause C. glabrata to disseminate often, although one exception was mice given high doses of dexamethasone for 4 days. These data support the hypothesis that the antibiotic-treated mouse intestine may be an epidemiological reservoir for C. glabrata and that this yeast tends to disseminate under specific clinical conditions.

Cyclophosphamide-induced agenesis of cerebral aqueduct resulting in hydrocephalus in mice

The present work was undertaken to reveal the mechanism of cerebral aqueduct agenesis found to result in hydrocephalus following intrauterine exposure to model teratogen, cyclophosphamide, in murine fetuses. A single dose of 10-mg/kg body weight cyclophosphamide was injected intaperitoneally to pregnant mice on day 10, 11 or 12 of gestation. Fetuses were collected through abdominal incision on day 18 and studied for various malformations of brain and cranium including hydrocephalus. Incomplete development and failure of canalization of the cerebral aqueduct were detected when serial sections of brain in coronal and transverse planes were studied under the microscope. Biotechnological investigations such as % DNA fragmentation, % viable cell count and cell proliferation assay were carried out on brain cells for further studies. Agenesis and non-canalization of the cerebral aqueduct resulted in increased pressure of CSF, which led to rupture of the aqueduct complicated by leakage and accumulation of CSF in brain substance forming a cavity containing CSF parallel and lateral to the unopened part of the cerebral aqueduct. Incomplete development along with non-canalization of the cerebral aqueduct resulted in blockage of CSF flow through the ventricles that manifest as internal hydrocephalus. External hydrocephalus on the other hand was detected where the CSF accumulated in the cavity formed inside the brain substance and established communication with the CSF in the subarachnoid space. Cyclophosphamide induced inhibition of mitosis and cell differentiation of ependymal cells reflecting a decreased % viable cell count and cell proliferation assay along with augmentation of apoptosis of brain cells quantified as increased % DNA fragmentation count, which were identified as the contributing factors underlying the agenesis and incomplete development of the cerebral aqueduct. The study also suggests that cell survival, proliferation, migration or differentiation of ependymal cells might have been affected, and we speculate that CSF may have an inducing role in the development and canalization of the cerebral aqueduct.

Modification of cyclophosphamide-induced clastogenesis and apoptosis in rats by alpha-lipoic acid

The aim of the present study was to investigate the protective efficacy of alpha-lipoic acid (LA) on the cyclophosphamide (CP)-induced chromosomal aberrations (CA) and apoptosis in the bone marrow of rats. Male Wistar rats of 140+/-20 g were categorized into eight groups. Five groups were administered CP (40 mg/kg body weight, intraperitoneally) to induce toxicity; four of these groups received a single intraperitoneal injection of LA at a dose of either 100 or 200 mg/kg body weight, and either 30 or 60 min prior to CP administration. A vehicle-treated control group and LA control groups were also included. Twenty-four hours after CP treatment, the frequency of CA in bone marrow cells were significantly increased in comparison with the controls. The CP-induced CA were associated with significant increase in DNA damage in the bone marrow as evidenced by increased single strand breaks, whereas in rats treated with LA and CP, the frequency of CA and single strand breaks were significantly decreased in comparison to those given CP alone. CP administration distinctly triggered the apoptotic and necrotic cell death, and LA pretreatment affected cell death by decreasing the number of apoptotic and necrotic cells. The protective effect of LA was found to be stronger at a dose of 200 mg/kg body weight than 100 mg/kg body weight dosage, indicating the dose dependent protective effect of LA. However, the protection by LA was not dependent on the time intervals between LA and CP administration. The results of this study illustrate the protective effect of LA on the CA and apoptosis induced by CP in the erythropoietic system of rats.

Chemoprotective effect of lipoic acid against cyclophosphamide-induced changes in the rat sperm

Treatment with cyclophosphamide (CP), a commonly used anticancer and immunosuppressive agent, may result in oligospermia and azoospermia. CP administration induces oxidative stress and is cytotoxic to normal cells. In this context, we have studied the effect of an established antioxidant, lipoic acid on its influence on CP-induced oxidative injury in rat sperm. In this study, we have assessed the possible protective efficacy of lipoic acid on the sperm characteristics, peroxidative damages and abnormal antioxidant levels in the epididymal sperm of CP-administered rats. Male Wistar rats of 140+/-20 g were categorized into four groups. Two groups of rats were administered CP (15 mg/kg body weight once a week for 10 weeks by oral gavage) to induce testicular toxicity; one of these groups received lipoic acid treatment (35 mg/kg body weight intraperitoneally once a week for 10 weeks; 24 h prior to CP administration). A vehicle treated control group and a lipoic acid drug control group were also included. CP-treated rats showed a significant decrease in sperm count and motility with an increase in dead and abnormal sperms. The epididymal sperm of untreated CP-exposed rats showed 1.9-fold increase in lipid peroxidation, along with a significant increase in protein carbonyl level. These changes were associated with significant increase in DNA damage in the sperm as evidenced by increased single strand breaks in fluorimetric analysis of DNA unwinding (FADU). In rats treated with CP, abnormal changes in the activities/levels of enzymic (superoxide dismutase, catalase and glutathione peroxidase) and non-enzymic (reduced glutathione, ascorbate and alpha-tocopherol) antioxidants, were also observed. Pretreatment with lipoic acid improved the semen quality and reduced the oxidative stress and DNA damage induced by CP, thereby demonstrating the protection rendered by lipoic acid.