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Background & Objective: The pattern of cell types in vertebrate embryos depend on the function of organizing centers, specialized cell groups that direct the fate of nearby cells through the secretion of inductive factors. Our previous studies showed that during early neural tube formation, the notochord is essential for the induction of ectoderm and for the subsequent differentiations of the neuroepithelium. It is well known that glycoconjugates are developmentally regulated expression on the surfaces of early embryonic cells and could therefore be involved in many critical morphogenetic and histogenetic events during embryonic development. Materials & Methods: In the present study, histochemical studies were carried out to detect the presence and distribution of terminal sugars during development of precursors of motor neurons within the developing spinal cord in balb/c mice. Embryos from day 9 to 14 of gestation were fixed and processed for lectin histochemical studies by using horseradish peroxidase labeled WFA with binding specificity for terminal N-acetylgalactosamine. Results: The first reaction was occurred weakly on the cells surface and extra cellular matrix just around the peripheral portion of floor plate on day 13 of gestation. It seems that these cells are developing premotor neurons, which will form the future motor neurons of the spinal cord. The reaction increased significantly and extended to the deep part of spinal floor plate by day 14. Conclusion: These data indicate that glycoconjugates containing N-acetylgalactosamine may play important roles in differentiation of the floor plate motor neuron and perhaps glia cells in final development of the ventral part of the spinal cord.

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Background and Objective: Neurons are injured under physical, chemical and pathological conditions. The effects of injuries in peripheral nervous system returns as retrograde to the cell body of neurons in central nervous system and causes brain and spinal degeneration. This study was done to evaluate the effect of aquatic extract of Cannabis sativa leaves on degeneration of alpha motoneurons in spinal cord after sciatic nerve compression in Rats.

Materials and Methods: This experimental study was carried out on thirty two male Wistar rats, weighing 300-350 grams. Animals were divided into four groups each consisting eight members A: control, B: compression, C: compression + treatment with 25 mg/kg aquatic extract, D: compression + treatment with 50 mg/kg aquatic extract. In order to induce compression in B, C and D, after cutting the right thigh muscle, Sciatic nerve of thigh was exposed to compression for 60 seconds using locker pincers. The first extract injection was done intraperitoneally immediately after compression and the second intera peritoneal injection was done 7 days later. 28 days after compression, the Lumbar spinal cord were dissected, fixed and stained with toluidine blue. The density of alpha motoneurons was measured using dissector and stereological methods. Data was analyzed with using Minitab-13 software, ANOVA and Tukey tests.

Results: Neuronal density was 611.5±34.2 and 1633.4±30.7 in compression and control groups respectively (P<0.001). There was a meaningful statistical increase in neuronal density of group C (1278.6±28.1) in comparing compression group (P<0.001). The neuronal density in group (D) (1549.8±87.7), significantly increased in comparison with group (B) (P<0.001).

Conclusion: This study showed that aquatic extract of Cannabis sativa leaves increases the density of alpha motoneurons in spinal cord after sciatic nerve compression in Rats. The increase in neuronal density is relevant to the amount of extract used.

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Background and Objective: Compression or sciatic axotomy induces neuronal death in spinal cord alpha motor neuron. This study was carried out to determine the effect of Nigella sativa seed alcoholic extract on spinal motor neuron density in anterior horn after sciatic nerve compression in rat. Materials and Methods: In this experimental study 24 wistar rats were divided into four groups A: control, B: compression, C: compression+treatment with 75 mg/kg alcoholic extract, D: compression+treatment with 50 mg/kg alcoholic extract. In control group muscle was exposed without any injury to sciatic nerve. In compression and treatment group, the right leg sciatic nerve compressed for 60 sec. After four weeks of post operation, L2-L4 and S1, S2 and S3 segments of spinal cord were sampled, processed, serially sectioned and stained with toluidine blue. The number of alpha motor neurons was counted using dissector method. Results: Neuronal density in compression group (650±32) significantly decreased in comparison with control group (1803±24). Neuronal density in C treated group (1581±47) and D treated group (1543±49) significantly increased compare to compression group (P<0.001). Conclusion: Alcoholic extract of Nigella sativa seed increased the density of alpha motor neurons in spinal cord after sciatic nerve compression in rats.

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Background and Objective: Previous studies have shown the adverse effects of gestational diabetes on hippocampal neuron density in animal model. This study was conducted to determine the effect of gestational diabetes on number of motor neuron in the ventral horns of spinal cord in 4, 8 and 12 weeks rat offspring. Materials and Methods: In this experimental study, 30 Wistar dams were randomly allocated in control and diabetic groups. Dams in diabetic group were received 40 mg/kg/bw of streptozotocin (STZ) at the first day of gestational day (GD) and control group were received an equivalent volume normal saline, intraperitoneally. Six offspring of cases and controls were randomly selected at the 4, 8, 12 postnatal weeks. Postnatal rats were scarified and sections (6 micrometer) were taken from the cervical part of spinal cord, stained by cresyl violet. A photograph of sections was produced using an Olympus BX51 microscope and a DP12 digital camera. The number of motor neurons in the right ventral horns of spinal cord was evaluated in 100000 μm2 area of spinal cord using OLYSIA Autobioreport software. Results: The number of motor neurons in 4 weeks rat offspring were reduced (24.90%) in gestational diabetics compared to controls (17.16±0.5 vs22.85±2.1, P<0.05). The motor neurons in 8 weeks rat offspring were reduced (32.95%) in gestational diabetics in comparison with controls (17.70±1.7 vs26.40±2.0, P<0.05). Also, the number of motor neurons in 12 weeks rat offspring were reduced (24.38%) in gestational diabetics in comparison with controls (17.83±0.7 vs23.58±1.4, P<0.05). Conclusion: The uncontrolled gestational diabetes reduces the number of motor neurons in the ventral horn of spinal cord in rat offspring.