Exploration of Maternal and Fetal Toxicity Risks for Metronidazole-Related Teratogenicity and Hepatotoxicity through an Assessment in Albino Rats

Metronidazole is the primary antimicrobial drug for treating acute and chronic vaginal pathogens during pregnancy; however, there has been insufficient research on placental disorders, early pregnancy loss, and preterm birth. Here, the potential activity of metronidazole on pregnancy outcomes was investigated. 130 mg/kg body weight of metronidazole was orally given individually to pregnant rats on gestation days 0-7, 7-14, and 0-20. Pregnancy outcome evaluations were carried out on gestation day 20. It was demonstrated that metronidazole could induce maternal and fetal hepatotoxicity. There is a significant increase in the activities of maternal hepatic enzymes (ALT, AST, and ALP), total cholesterol, and triglycerides compared with the control. These biochemical findings were evidenced by maternal and fetal liver histopathological alterations. Furthermore, metronidazole caused a significant decrease in the number of implantation sites and fetal viability, whereas it caused an increase in fetal lethality and the number of fetal resorptions. In addition, a significant decrease in fetal weight, placental weight, and placental diameter was estimated. Macroscopical examination revealed placental discoloration and hypotrophy in the labyrinth zone and the degeneration of the basal zone. The fetal defects are related to exencephaly, visceral hernias, and tail defects. These findings suggest that the administration of metroniazole during gestation interferes with embryonic implantation and fetal organogenesis and enhances placental pathology. We can also conclude that metronidazole has potential maternal and fetal risks and is unsafe during pregnancy. Additionally, it should be strictly advised and prescribed, and further consideration should be given to the associated health risks.

Distribution of nitric oxide-producing cells along spinal cord in urodeles

Nitric oxide is a unique neurotransmitter, which participates in many physiological and pathological processes in the organism. There are little data about the neuronal nitric oxide synthase immunoreactivity in the spinal cord of amphibians. In this respect, the present study aims to investigate the distribution of nitric oxide producing cells in the spinal cord of urodele and to find out the possibility of a functional locomotory role to this neurotransmitter. The results of the present study demonstrate a specific pattern of NADPH-d labeling in the selected amphibian model throughout the spinal cord length as NADPH-d-producing cells and fibers were present in almost all segments of the spinal cord of the salamander investigated. However, their number, cytological characteristics and labeling intensity varied significantly. It was noticed that the NO-producing cells (NO-PC) were accumulated in the ventral side of certain segments in the spinal cord corresponding to the brachial and sacral plexuses. In addition, the number of NO-PC was found to be increased also at the beginning of the tail and this could be due to the fact that salamanders are tetrapods having bimodal locomotion, namely swimming and walking.

Ultrastructural study of the lateral line neuromasts in tadpoles of Saudi Bufo dhufarensis and Rana ridibunda

Neuromast (hair cells) structure in Bufo dhufarensis and Rana ridibunda larvae was observed by Scanning Electron Microscopy (SEM). Neuromasts were found arranged in one well-defined line in the head, body, and tail regions forming the lateral line and also found haphazardly scattered in most of the body parts. Their number was significantly high in the head region, and then it gradually decreased along the posterior end of the body. The structure of neuromasts in these three regions was basically similar for each species. In Rana, neuromasts were found few in number, either spherical or oval in shape lacking hair-like structure except in the tail region where hair cells were found. While in Bufo, neuromasts were numerous. Long kinocilia and many stereocilia were found in the neuromasts. Kinocilia were either solitary or in clusters. In addition to the main functions of the neuromasts we discovered a new function which was not found in previous researches, neuromasts were also used to remove any attached object on the tadpole's skin, by directing the kinocilium to the object thing and rolling onto it then detaching it outwards.

Fgf-2 in astroglial cells during vertebrate spinal cord recovery

Fibroblast growth factor-2 is a pleiotrophic cytokine with neurotrophic and gliogenic properties. It is known to regulate CNS injury responses, which include transformation of reactive astrocytes, neurogenesis, and promotion of neurotrophic activities. In the brain, it is localized in astrocytes and discrete neuronal populations. Following both central and peripheral nervous system injury, astrocytes become reactive. These activated cells undergo hypertrophy. A key indicator of astrocyte activation is the increased accumulation of intermediate filaments composed of glial fibrillary acidic protein (GFAP). Following physical insult of brain or spinal cord, reactive astrocytes show increased FGF-2 immunoreactivity. Thus, FGF-2 appears to participate in astrocytic differentiation and proliferation and a good candidate for astrocytic function regulation in healthy, injured, or diseased CNS. To further investigate the cellular mechanisms underlying FGF-2 restorative actions and to analyze the changes within astroglial cells, we studied the localization of GFAP and FGF-2 in adult intact and injured Pleurodeles CNS. Our results show that spinal cord injury triggers a significant increase in FGF-2 immunoreactivity in reactive astrocytes at sites of insult. In addition, these results were time-dependent. Increase in FGF-2 immunoreactivity along the CNS axis, starting 1-week post-injury, was long-lasting extending to 6 weeks. This increase was accompanied by an increase in GFAP immunoreactivity in the same spatial pattern except in SC3 where its level was almost similar to sham-operated animals. Therefore, we suggest that FGF-2 may be involved in cell proliferation and/or astroglial cells differentiation after body spinal cord transection, and could thus play an important role in locomotion recovery.

A role for effectors of cellular immunity in epimorphic regeneration of amphibian limbs

Immune modulation of regeneration of amphibian appendages is suggested, but not proven, by previous studies. Earlier studies have not demonstrated effects of treatments on both epimorphic regeneration and immune responses or restoration of regeneration by specific reversal of immunomodulation. Cyclosporin A (CsA) and interleukin-2 (IL-2) were used in this study to demonstrate the effects of immune suppression and its reversal, on allograft rejection and forelimb regeneration. When administered alone, CsA suppressed rejection of skin allografts and induced a dose-dependent retardation of regeneration. IL-2, administered alone, did not affect allograft rejection or regeneration. However, when combined with CsA, IL-2 abrogated or reversed effects of CsA on both allograft rejection and forelimb regeneration, in a dose-dependent manner. The selective focus of CsA's action and the ability of IL-2 to overcome and reverse these effects strongly suggest that T-lymphocytes participate in or contribute to expression of epimorphic regeneration of amphibian appendages. Further studies are required to better characterize this role.