Cell Journal (Yakhteh)
Year:1999 | Volume:1 | Issue:2|Papers Count:9

Introduction: The incidence of sperm and oocyte premature chromosome condensation (PCC) in the failed fertilized oocytes that were taken after routine in viro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) programs were investigated. Materials and methods: In this study, 364 air-dried preparation of failed fertilized oocytes after either IVF or OCSI procedures were analyzed. The zona pellucida of the oocyte were removed by thyrod"e s acid. The oocytes then were subjected to a hypotonic solution for 15-20 minute. This solution consisted of sodium chloride. disTilled water and sodium citrate, which resulted in the swelling of the cell. The swelled oocytes were fixed sequentially in three different fixatives then they were stained in 10% Giemsa and examined with light microscope at x1000. Results: A high frequency of intact sperm head were noticed in the failed fertilized oocytes. The number of intact sperm head were higher in ICSI procedure than IVF (46.5% versus 30.5%), however the difference was statistically not significant. On the Other hand, PCC of the sperm were significantly in ICSI higher than IVF (16.1% gersus 8.8%, P< 0.05). Oecondensed chromatins and degenerated) chromosome were also seen in some oocytes. Conclusions: An abnormal chromatin decondensation or PCC of sperm head and oocyte nucleus occurs in the failed fertilized oocytes after IVF procedure. Several factors can be associated with the above abnormalities such as the failure of oocyte activation or an immature retrieval of oocytes. The presence of an intact sperm head may indicate that the sperm nucleus is not accessible to ooplasmic factors, where the sperm nucleus should interact with chromosome condensing factors. This may result in the induction of PCC because of the non-activated oocyte has remained in metaphase II.

Introduction: This study was initiated to examine the effect of the ampullary and the isthmic primary cell cultures of human oviduct during long-term co-culture on two-cell mouse embryos. Materials and Methods: Using a mechanical procedure, epithelial cells from ampullary (A) and isthmic (I) regions of the human oviduct were isolated and cultured in Ham"s F-10 with 10% fetal calf serum (FSC). The 2-cell embryos were prepared from Albino Swiss mice, which were co-cultured in Ham"s F-10 with 10% FSC with either primary A-cell culture or primary I-cell for 5 days. The control group was Albino Swiss mouse embryos which were maintained in the same culture medium without co-culturing. Results: After 120h , the co-cultured embryos groups (A and I) had more blastocyts (4% an 41% respectively) and hatched embryos (22% both) as they were compared with the control which showed 16 and 8 percentages for blastocyts and hatched embryos respectively. The levels of significance were high (P<0.001 both). Moreover, in first 48h, the development rete was more in the embryos which were co-cultured with A-cell than that of I-cell (P<0.001 for 24h and p<0.01 for 48h.). Conclusion: The results suggest that an unknown factor which may be released the epithelial cell in the co-culture stimulating the development of the mouse embryos. Moreover, the in virto development of embryos may be more supported by human A-cell than human I-cell.

Introduction: Mouse embryos can successfully be frozen with sucrose and propandiol. However, different developmental stages of mammalian embryos have shown to have various capacities to undergo freeze-thawing procedure. In the present study, the ability of 1,2,4 and 8-ell mouse embryo to tolerate the freeze-thawing procedure was investigated and the effect of this procedure on the further in vitro development. Materials and Methods: One, 2,4 and 8-cell mouse embryos were flushed from the excised uteri of the gonadotropin treated mice. Morphologically normal embryos were frozen slowly with propandiol and sucrose and thawed rapidly. The survived embryos were cultured for 4-5 days and their development in the later stages such as hatching blastocyst was compared with non-frozen embryos. Results: The rate of survival for 1-cell embryos was higher than the other stages. The survival rates were 91, 80, 82 and 85% for 1, 2, 4 and 8-cell embryos respectively.The rate of development of the embryos beyond the late blastocyst stage was greater in 4 and 8-cell embryos. In addition to that, the 4-cell embryos developed to hatching blastocyst as it is compared with 2 and 8-cell stages embryo (P0<0.05). Conclusion: The different development stages of mouse embryos can successfully be frozen. However, the survival rate and post-thawing development is correlated with the developmental stage of the frozen embryos.

Introduction: Sodium valproate is an anti convulsant drug which has been used to treat epileptic patients for last decades. Even a pregnant patient have to use this drug for the treatment of epileptic seizure. The purpose of this investigation is to study the effect of this medicine on the embryo in the mouse. Materials and Methosd: Eight pregnant mice were given 200 mg/kg (i.p.) of sodium valproate on the day of gestation at three times intervals at 0,6 and 12 hrs. The control group consisted of seven pregnant mice which were injected sterile distilled water. On day 18 of gestation, all the embryos from both groups were removed, cleared and stained with Alizarine Red and Alcian Blue. Results: The embryos of the experimental group had an increase in the number of cartilage particles of vertebral body, adhesion of vertebral bodies, variability of the numbers of the ossification centers and the adhesion of the lateral ossification centers. Also spina bifida occulta was seen. Conclusion: Administration of sodium valproate to pregnant mouse can induce a variety of vertebral abnormalities including spina bifida occulta.

Introduction: Osseous tissue developes via either endochondral (EC) or intramemberanous (IM) ossification. The bone matrix gelatin (BMG) from both developmental types can induce bone formation when implanted in the muscle of the rat. In this research, the resorption of IM-BMG particles, inductivity of IM-BMG and the nature of heterotropic calcification was evaluated at implantation site. Materials and Methods: The frontal bones from (60) male Spargue Dawely rat (4-8 weeds old) were removed, cleaned, crushed to small chips and used to prepare BMG according to Urist et al, and 2 mg of BMG was implanted in the rectus abdominis muscles of the experimental group, while the control group received a denatured BMG. After 7, 10, 25 and 35 days of implantation, the implants were removed and processed for light and electron microscopes. Results: The inductive capacity of IM-BMG is lesser than EC-BMG, the resoption of IM-BMG is longer than EC-BMG. The acellular mineral deposite (AMD) was reported only in EC-BMG, while AMD was also noticed in this study with IM-BMG. Conclusion: The conclusion of this study was that both EC-BMG and IM-BMG have similar bone inducing factors for heterotropic calcification in the implantation site. The resoption of implant is longer in IM-BMG than EC-BMG, but the factors which are involved in the resoption rate are similar.

Introduction: The teratogenic effect of caffeine depends on the dosage and the route of administration. A daily oral dose of caffeine (80 mg/kg) is tetrogenic for rat. In present study, the teratogenic effects of caffeine on the development of bones and the resoption of skeletal cartilage in the rat embryo were quantitatively evaluation. Materials and Methods: Three groups of pregnant rats were used in the study, which were pregnant from the first time. The first experimental group received 175 mg/kg of 1% caffeine on the fourteenth day of the pregnancy, while the second experimental group received 80 mg/kg of 1% caffeine on days 14, 15 and 16 of the pregnancy. The third group was kept as control group. On day 20 and 21 of the pregnancy, the animal were sacrified and 209 embryo were collected which were used to evaluate the teratogenic effect of caffeine. The left caudal limbs of these embryo were cut, fixed, decalcifed, processed in paraffin, serially sectioned and stain with Hematoxyline and Eosin. The volumes of periosteum, perichondrium, trabecular bone, collar bone, whole and cartilage were calculated. A camera lucida was used for acquisition of the primary data. The analysis of the variance were used to compare the statistical difference among the parameters. Results: There were statistically significant reduction in all the parameters in the experimental groups as they were compared with the control group. No significant difference was noticed between the experimental groups. Conclusion: The injection of caffeine to pregnant rats causes a reduction in the extracellular bone matrix and delays the bone formation in their off spring.

Introduction: The hippocampus was recognized as an important focus of epileptic seizures. A long-term potentiation (LTP) like that of epileptiform activities is considered as synaptic which has been observed for the first time in hippocampal formation. The purpose of the present study was investigate the synaptic plasticity induced by tetanic stimulation at CA1 area of the rat hippocampal slices that were susceptible to epileptic seizures. Materials and Methods: Epileptiform activities in these slices were induced by the application of pentylenetetrazol (PTZ, 3mM) for 20 miniutes. Neural activity in the form of population spikes in pyramidal cell of CA1 area was recorded before and after tetanic stimulation r PTZ application. Input-output curves of amplitude and delay of population spikes were used to find out changes in synaptic efficacy. Results: Twenty minutes after PTZ application, and five minutes after tetanic stimulation (in control group), input-output curves had shifted to the left and the shift remained for at least 60 minutes after PTZ washout or tetanic stimulation. PTZ application also led to the appearance of after potentials which maintained for about 30 minutes after PTZ washout. The increase of population spike amplitude induced by tetanic stimulation, in PTZ-treated slices was lower than that of the control one, but the difference between the control and PTZ treated slices was not significant. In addition, to that potentials appeared in PTZ-treated slices following the tetanic stimulation. Conclusion: The results indicate that PTZ administration for 20 minutes is after sufficient to make up a stable model of epileptic activity. PTZ, like the LTP induced by tetanic stimulation, shifts the input-output curve to the left. Potentiation resulted from LTP was not occluded by the prior PTZ. Therefore, to induce the epileptic activity, a background of potentiation in neural activity is necessary.

Introduction: Parkinson"s disease (PD) is a human neurodegenerative disorder which is associated with a massive and progressive degeneration of dopaminergic neurons in subistantia nigra (SN). There is a strong evidence of an oxidative stress participates in the etiology of PD. Materials and Methods: The rats were divided into sham-operated, experimental and vitamin E-treated groups. For anesthesia, a mixture of ketamine and xylazine was used (i.p.). The experimental group received 5ml of 0.9% saline containing 6-hydroxydoppamine (6-OHDA) and 2% ascorbic acid in addition to 0.8 ml/kg of propylene glycol (PG, i.m.), and sham-operated group received and identical volume of saline- ascorbate in left side of striatum. The vitamin E-treated group received D-a-tocopheryl acid succinate (24 I.U./Kg, i.m.) dissolved in PG, one hour before the surgery and three times a week for a month after the surgery. Tyrosine hydroxylase (TH) immunohistochemistry in SN and striatum was used as an index for the tratment efficacy. Results: The results, showed than an over all reduction (47%) in the number of TH immunoreactive (IR) neurons in the left SN-cell was observed in 6-OHDA lesioned group (P<0.005). However, the cell loss had attenuated to 18% in vitamin E-treated animals (P<0.05) compared with the right side. A non-significant difference in the number of TH-positive neurons between the sham-operated and the vitamin E-treated groups was noticed. A microscopic inspection of the injection site in the striatum revealed that in all treated animal, there was a dense halo of TH-IR fiber around the needle track. A grater loss of TH-IR fiber has been observed around the injection site in the experimental group. Conclusion: Vitamin E-treatment can enhance the resistance and longitivity of dopaminergic nigral neurons against the oxidative stress induced by 6-OHDA. The results may prompt an interest in the use of vitamin E as a neuroprotective agent in the treatment of PD.