The effect of experimental epilepsy induced by penicillin administration during pregnancy on nestin expression in the immature rat cerebellum. A light, electron microscopic, and immunohistochemical study

Effects of Melatonin on the Cerebellum of Infant Rat Following Kaolin-Induced Hydrocephalus: a Histochemical and Immunohistochemical Study

Hydrocephalus is a developmental disorder causing abnormally collected cerebrospinal fluid within the cerebral ventricles. It leads to bigger skulls and many dysfunctions related to the nervous system. Here, we addressed whether exogenous melatonin administration could reverse the clinical features of kaolin-induced hydrocephalus in infantile rats. A controlled double-blinded study was conducted in 2-week-old 45 Wistar albino rats, which were divided into three groups: Group A, the control group, received intracisternal sham injection with solely the needle insertion; group B, the hydrocephalus group, was treated with isotonic NaCl after kaolin injection; and group C, the hydrocephalus + melatonin group, was given i.p. exogenous melatonin at a dose of 0.5 mg/100 g body weight after kaolin injection. Histological and immunohistochemical analyses were performed after the induction of hydrocephalus and melatonin administration. Glial fibrillary acidic protein was stained by immunohistochemical method. TUNEL method was used to define and quantitate apoptosis in the cerebellar tissues. Statistical analysis was performed by nonparametric Kruskal-Wallis H test, and once significance was determined among means, post hoc pairwise comparisons were carried out using Mann-Whitney U test. We found that melatonin administration significantly ameliorated ratio of substantia grisea area/substantia alba area in the cerebellum of infantile rats. Histologically, there was a significant reduction in the number of cerebellar apoptotic cells after the hydrocephalus induced by kaolin (P < 0.05). Our results clearly revealed that the histopathological changes in the cerebellum were reversed by systemic melatonin administration in infantile rats with kaolin-induced hydrocephalus. Nevertheless, further studies are needed to suggest melatonin as a candidate protective drug in children with hydrocephalus.

The effect of PTZ-induced epileptic seizures on hippocampal expression of PSA-NCAM in offspring born to kindled rats

BACKGROUND

Maternal epileptic seizures during pregnancy can affect the hippocampal neurons in the offspring. The polysialylated neural cell adhesion molecule (PSA-NCAM), which is expressed in the developing central nervous system, may play important roles in neuronal migration, synaptogenesis, and axonal outgrowth. This study was designed to assess the effects of kindling either with or without maternal seizures on hippocampal PSA-NCAM expression in rat offspring.

METHODS

Forty timed-pregnant Wistar rats were divided into four groups: A) Kind+/Seiz+, pregnant kindled (induced two weeks prior to pregnancy) rats that received repeated intraperitoneal (i.p.) pentylenetetrazol, PTZ injections on gestational days (GD) 14-19; B) Kind-/Seiz+, pregnant non-kindled rats that received PTZ injections on GD14-GD19; C) Kind+/Seiz-, pregnant kindled rats that did not receive any PTZ injections; and D) Kind-/Seiz-, the sham controls. Following birth, the pups were sacrificed on PD1 and PD14, and PSA-NCAM expression and localization in neonates' hippocampi were analyzed by Western blots and immunohistochemistry.

RESULTS

Our data show a significant down regulation of hippocampal PSA-NCAM expression in the offspring of Kind+/Seiz+ (p = 0.001) and Kind-/Seiz+ (p = 0.001) groups compared to the sham control group. The PSA-NCAM immunoreactivity was markedly decreased in all parts of the hippocampus, especially in the CA3 region, in Kind+/Seiz+ (p = 0.007) and Kind-/Seiz+ (p = 0.007) group's newborns on both PD1 and 14.

CONCLUSION

Our findings demonstrate that maternal seizures but not kindling influence the expression of PSA-NCAM in the offspring's hippocampi, which may be considered as a factor for learning/memory and cognitive impairments reported in children born to epileptic mothers.

Morphometrical study of polysialylated neural cell adhesion molecule positive cells in rat pups hippocampus following induction of seizure during pregnancy

BACKGROUND

The polysialylated neural cell adhesion molecule (PSA-NCAM) is expressed in developing brain. Fetal brain damage is caused by different conditions such as seizure and hypoxia. The present study was designed to investigate the effect of maternal seizures on the number of PSA-NCAM positive cells in pup's hippocampus.

METHODS

Female Wistar rats were divided into four groups: (a) kindled rats which received PTZ (40 mg/kg, i.p.) during pregnancy from embryonic day 14-19 (E14-E19) every 48 h, (b) kindled rats which did not receive PTZ during pregnancy, (c) non-kindle, pregnant rats which received PTZ injection (40 mg/kg, i.p.) during pregnancy from E14 to E19 every 48 h, and (d) non-kindle, pregnant rats which received injection with an equal volume of normal saline as sham controls. At postnatal day 14 (PD14), rat pups were perfused, and their brain were fixed, embedded and coronal sections stained by immunohistochemistry method. The number of PSA-NCAM positive cells per unit area in the pup's hippocampus was counted.

RESULTS

The number of PSA-NCAM positive cells in the CA1, CA3, and DG fields of pup's hippocampus, which was obtained from mothers who experienced PTZ injection during pregnancy, was decreased approximately 2.6 (P = 0.001), 2 (P = 0.001), and 2.1 (P = 0.001) times compared with non-PTZ treated maternal groups, respectively.

CONCLUSIONS

Our study showed that maternal seizures reduced the number of neurons and also PSA-NCAM positive cells per unit area in the offspring hippocampus that it may cause impairment in hippocampal functions.

Efficacy of melatonin on offspring liver maturation in pinealectomized pregnant rats subjected to experimental epilepsy

BACKGROUND AND AIMS

In clinical practice, maternal epilepsy is a disabling disease for newborn infants, but current data concerning the effect of epileptic phenomena in pregnant mothers on newborns are still limited. This study was undertaken to investigate the effects of pinealectomy (Px) and melatonin treatments on the morphological changes in the liver tissue of newborn rats following experimental epilepsy during pregnancy.

METHODS

Female Swiss Albino rats were divided into five groups: intact control group; saline control group; epilepsy group; epilepsy plus Px group; and melatonin-treated epilepsy plus Px group. At one month after Px, an acute grand mal epileptic seizure was induced by penicillin-G during their pregnancy in all animals except the control groups. On the neonatal first day, newborn rats were perfused with intracardiac fixative solution, and then livers were removed and processed for toluidine blue, periodic acid-Schiff (PAS) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) reactivity.

RESULTS

Normal migration and hepatic maturation were determined in the postnatal rat liver in the control groups, while the morphological structure of the liver in the epilepsy and epilepsy plus Px groups corresponded to the early embryonic period. In the melatonin-treated epilepsy plus Px group, the number of TUNEL positive cells decreased significantly compared to both epilepsy and epilepsy plus Px groups; however, there was no statistically significant difference from the control groups as a result of melatonin activity.

CONCLUSIONS

Some histological findings consistent with chronic fetal distress in newborns of mother rats with epilepsy and Px were observed. Melatonin could be a candidate protective drug for the development of liver tissue in pregnant patients with epilepsy.

Beneficial effects of melatonin on morphological changes in postnatal cerebellar tissue owing to epileptiform activity during pregnancy in rats: light and immunohistochemical study

Although it has been demonstrated that maternal epilepsy has some harmful effects on newborn individuals, current data concerning the effects of epileptic phenomena in pregnant mothers on newborn pups are still limited. This study was undertaken to investigate the changes in the cerebellum of newborns of pinealectomized rats subjected to experimental epilepsy during pregnancy. In our study, the rats were randomly divided into six groups: intact control group, anesthesia control group, epilepsy group, melatonin-treated epileptic group, surgical pinealectomy group, and group of melatonin treatment following pinealectomy procedure. At 1 month after pinealectomy, an acute grand mal epileptic seizure was induced by 400 IU penicillin-G administration into their intrahippocampal CA3 region during the 13th day of their pregnancy in all animals except intact control group. On the neonatal first day, pups were perfused transcardially and the cerebellums removed were processed for light microscopic and immunohistochemical studies. Normal migration and maturation were determined in the postnatal rat cerebellum in both intact control and anesthesia (ketamine-xylazine) control groups, but the morphological structure of cerebellum in the epilepsy control group corresponded to the early embryonal period. It was found that experimental epilepsy or pinealectomy procedure enhanced nestin immunoreactivity, but exogenous melatonin treatment (30 microg/100 g body weight, i.p.) following pinealectomy inhibited increased nestin expression induced by melatonin deprival in vermis region of newborn rat cerebellum (P < 0.001). Our results confirm that epileptic seizures during pregnancy may impair neurogenesis and neuronal maturation in newborns, which are more dramatic in the presence of melatonin deficiency during pregnancy, explaining more harmful effects of epileptic seizures to embryos of aged mothers. To the best of our knowledge, this is the first study reporting the effects of maternal epilepsy during pregnancy in pinealectomized rats on nestin immunoexpression in the newborn rat cerebellum.

Influence of penicillin-induced epileptic activity during pregnancy on postnatal hippocampal nestin expression in rats: light and electron microscopic observations

OBJECTS

Current data concerning the effects of maternal epileptic phenomena on newborns are limited. In clinical practice, therefore, it is difficult to suggest proper guidelines on this issue. This study was carried out to investigate the morphological changes in the hippocampus of newborn pups of rats subjected to experimental epilepsy during pregnancy.

METHODS

Eighteen Swiss Albino rats were randomly divided into three groups (n=6): experimental group, saline-injected sham surgery group, and intact control group. In the experimental group of rats, an acute grand mal epileptic seizure was induced by 400 IU penicillin-G administration into their intra-hippocampal CA3 region with a stereotaxic device during the 13th day of their pregnancy. On the first neonatal day, pups were perfused with intracardiac fixative solution under anesthesia, and newborn hippocampi were dissected surgically for light and electron microscopic examinations. In an immunohistochemical study using Rat-401 mono-clonal antibody and peroxidase, nestin expression was analyzed in the developing hippocampal tissue.

RESULTS

Histologically, normal migration and hippocampal maturation were determined in the newborn rat hippocampus in the control and the sham-operated groups. It was observed that the morphological structure of hippocampus in the experimental group corresponded to the early embryonal period. Most importantly, it was found that nestin (+)cell density was increased in the experimental epilepsy group in contrast to the control and sham groups.

CONCLUSION

It has been concluded that epileptic seizures during embryonic life may cause impaired hippocampal neurogenesis and maturation,explaining the potentially harmful effects of epileptic seizures on the embryo at the early stage of neuronal differentiation. This is the first report regarding the alterations in nestin expression in newborn rat hippocampus. In the light of such findings, it will also be necessary to evaluate the functional consequences of a va-riety of epileptic seizures on learning and memory in neonates.