| Objective We evaluated the morphometric characteristics and distribution of the NADPH-d positivity in the spinal cord and medullary oblongate of the young adult pigeons.From the point of view of NADPH-d histochemical staining,how the the gray matter above central canal and dorsal column of lumbosacral was open and how to close in detail.To explore whether there was age-related NADPH-d positive body(ANB)in the lumbosacral spinal cord?gracile nucleus(Gr)?cuneate nucleus(Cu)of aged pigeons and mice.Were ANBs as a neurodegeneration prevalent in different species? By comparing the similarities and differences among aged pigeons,aged rats and aged mice,the far-reaching significance of the existence of ANBs were further elaborated.Methods Animal experiments: the experimental animals were divided into two groups: aged group: 15 healthy aged pigeons(Columba livia)(five in 9,14 and 16 years respectively);10 healthy aged SD rats(18 months);10 healthy aged C57BL/6J mice(18 months).Young group: 10 healthy young pigeons(Columba livia)(1 year);10 healthy young SD rats(2 months);10 healthy young C57BL/6J mice(2 months).There was no limit to male and female.Animals in each group were anesthetized by intraperitoneal injection,exposured to the heart,fixed by transventricular perfusion.Getting out the spinal cord and medulla oblongata from animals.At the same time,dorsal root ganglia(DRG)of lumbosacral enlargement in young adult pigeons(1 year)and aged pigeons(16year)were carefully removed.According to the knowledge of anatomy,it could be divided into cervical,thoracic,lumbar and sacral segments.The Gr and Cu of the medulla oblongata were fully exposed.The tissue was dehydrated by sucrose and cut into 40 micron frozen sections.NADPH-d histochemical staining was used to observe the distribution in the spinal cord segments and the medulla oblongata of young and aged pigeons,young and aged SD rats,young and aged C57BL/6J mice.The expression of Neu N,GFAP,Iba1,MAP2 and VIP in the spinal cord of young and aged pigeons was observed by immunofluorescence.Results NADPH-d histochemical staining results: NADPH-d positive neurons were more numerous in the dorsal horn,around the central canal of the CT in the thoracic and lumbar segments and scattered neurons occurred in the ventral horn of every spinal segment of young adult pigeons.NADPH-d positive neurons also occurred in the white matter of spinal cord.Statistical analysis showed that the distribution of lumbosacral segment was more significant than that of lumbosacral segment.Compared with younger animals,the number of NADPH-d positive neurons in the dorsal horn of each spinal cord segment in old animals decreased in varying degrees(P < 0.05),except for the thoracic segment.From the point of view of NADPH-d histochemical staining,how the the gray matter above central canal and dorsal column of lumbosacral was open and how to close in detail.Immunofluorescence test results showed that compared with the younger group,the expression of Neu N and MAP2 in the lumbosacral spinal cord of pigeons in the older group decreased(P < 0.05),while the expression of GFAP,Iba1 and VIP increased(P < 0.05).It is worth noting that no ANBs like that found in the dorsal horn and dorsal commissural nucleus(DCN)of the lumbosacral segment of the aged rats was found in the aged pigeons.However,ANBs were found in the dorsal column?Gr?Cu?cuneatus externus nucleus(Cu E)of the aged pigeons.In addition,ANBs were also found in the Gr and DCN of lumbosacral segment in aged mice.The number of ANBs in Gr of aged rats was larger than that of aged pigeons,and so was the ANBs in dorsal column.Conclusions 1?NADPH-d positive neurons were more numerous in the dorsal horn,around the central canal and scattered in the ventral horn of every spinal segment.NADPH-d positive neurons also occurred in the white matter of spinal cord.The distribution of different spinal segments was different.But,compared with young adult pigeons,the number of NADPH-d positive neurons in the dorsal horn of spinal cord,CT and clarke's column(CIC)of the aged animals decreased in varying degrees.This indicated that neurons were damaged,and the decrease of Neu N and MAP2,the increase of expression of GFAP,Iba1 and VIP also confirm this problem.2?ANBs were not found in the lumbosacral spinal cord of aged pigeons,which similar to those found in aged rats.However,ANBs were found in the dorsal column?Gr?Cu?Cu E of the aged pigeons.In addition,ANBs were also found in the Gr and DCN of lumbosacral segment in aged mice.At least,it can be said that ANBs as one kind neurodegeneration were prevalently among different species.Therefore,we could speculate whether ANBs could be used as a marker of aging-related neurodegeneration. |
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