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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: 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.

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Background and Objective: Transaction or laceration and compression of peripheral nerves in accidents and different circumstances resulting Wallerian degeneration which go back to perikaryon through retrograde reaction. This study was done to determine the effect of alchohlic extract of Achillea wilhelmsii on density of motor neurons of spinal cord after sciatic nerve compression in male Wistar rats.

Methods: In this experimental study, 30 male wistar rats were randomly allocated into 5 groups: group A: control, group B: compression, group C: compression and treatment with 50 mg/kg/bw of ethanolic extract, group D: compression and treatment with 75 mg/kg/bw of ethanolic extract and group E: compression and treatment with 100 mg/kg/bw of ethanolic extract of Achillea wilhelmsii. After anesthetizing rats, skin and sub cutaneous muscles of right thigh were cut to sciatic nerve appears. Then, compression of sciatic nerve was done by a surgical forceps for 60 seconds, followed by suturing muscle and skin. Extract injection was done intraperitoneally for three weeks after compression. Group A and B were received normal saline. 28 days after compression, samples were prepared from lumbar spinal cord under perfusion method and histological sections were provided serially. After staining, density of motor neurons was calculated by dissector method.

Results: Neuronal density in the compression group (707±38.56) significantly reduced in compare to control group (1740±49.81), (P<0.05). Neuronal density in group C (1208±57.58), group D (1370±33.91), and group E (1437±64.46) significantly increased in compare to compression group (P<0.05), respectively.

Conclusion: Ethanolic extract of Achillea wilhelmsii increased neuronal density of rat's spinal cord after compression of sciatic nerve.