Kott J N, Westrum L E
Department of Neurological Surgery, University of Washington, Seattle 98195, USA.
Int J Dev Neurosci. 1996 Nov;14(7-8):961-70. doi: 10.1016/s0736-5748(96)00043-3.
In an effort to identify and understand the laminar disorganization that occurs in the transplanted (TX) rat olfactory bulb (OB), we examined the development of fiber systems within these TX OBs. One antibody for olfactory marker protein (OMP) was used to identify axons of mature olfactory receptor neurons (ONs) and a second antibody, for a growth-associated protein (GAP-43), provided a marker for all extending or immature fibers. Donor OBs were taken from fetuses on embryonic days 14 or 15 (sperm-positive day is zero) and TX directly into the cavity produced by removal of an OB in 1-day-old hosts of the same strain. After survival times of 1 and 2 weeks and at maturity, adjacent 8 microns paraffin sections from the TX material were examined for OMP and GAP-43 reactivity. Fiber bundles, reactive for OMP, were found within the TX by 1 week post-TX, indicating rapid re-innervation of the donor OB by ONs. The appearance of OMP reactivity gradually shifted from tightly packed, well-defined fiber bundles at 1 week post-TX to a diffuse reticulated pattern of individual fibers emerging from bundles at maturity. The OMP-reactive fiber bundles of the TX OB also contained GAP-43-reactive fibers, but GAP-43 reactivity also extended to other (OMP-negative) bundles and fields. Reactivity for GAP-43 in the TX OB was nearly ubiquitous at 2 weeks post-TX but, as development progressed (in both the TX and normal OB), such reactivity gradually decreased. Thus, while maturation in sensory afferent fiber systems in the TX OB may be delayed, it eventually follows a pattern similar to that in the normal OB, suggesting that factors other than the timing of fiber extension may be responsible for the laminar disorganization of the TX OB.
为了识别和理解移植（TX）大鼠嗅球（OB）中出现的层状结构紊乱，我们研究了这些TX嗅球内纤维系统的发育情况。一种针对嗅觉标记蛋白（OMP）的抗体用于识别成熟嗅觉受体神经元（ONs）的轴突，另一种针对生长相关蛋白（GAP-43）的抗体则为所有延伸或未成熟的纤维提供标记。供体嗅球取自妊娠第14或15天（以精子着床日为第0天）的胎儿，并直接移植到同品系1日龄宿主中去除嗅球后形成的腔内。在存活1周和2周以及成熟时，对TX材料相邻的8微米石蜡切片进行OMP和GAP-43反应性检测。移植后1周，在TX嗅球内发现了对OMP有反应的纤维束，表明嗅球神经元对供体嗅球进行了快速的重新支配。OMP反应性的外观从移植后1周紧密排列、界限清晰的纤维束逐渐转变为成熟时从束中出现的单个纤维的弥漫网状模式。TX嗅球中对OMP有反应的纤维束也含有对GAP-43有反应的纤维，但GAP-43反应性也扩展到其他（OMP阴性）束和区域。TX嗅球中GAP-43的反应性在移植后2周几乎普遍存在，但随着发育进程（在TX嗅球和正常嗅球中都是如此），这种反应性逐渐降低。因此，虽然TX嗅球中感觉传入纤维系统的成熟可能会延迟，但最终会遵循与正常嗅球相似的模式，这表明除了纤维延伸的时间外，其他因素可能是TX嗅球层状结构紊乱的原因。
