Granholm A C, Seiger A
Med Biol. 1981 Feb;59(1):51-7.
Fetal brain tissue pieces containing locus coeruleus noradrenaline neurons were combined with sequentially or simultaneously grafted irides in the anterior eye chamber of thyroidectomized or normal host rats. The aim was to reveal possible morphological alterations in the adrenergic fibres innervating the iris grafts, induced by thyroid hormone deficiency, and to compare that possible hormone dependency with what has been found before in host irides innervated by locus coeruleus neurons. Nerve fibre outgrowth was evaluated in iris whole mounts, using Falck Hillarp fluorescence histochemistry. The distribution of locus-coeruleus-derived fibres on host irides was markedly altered in the thyroidectomized hosts. The number of fluorescent axon bundles was significantly decreased, and the intermingled varicose nerve fibre plexus contained numerous accumulations of fluorescent material. In the iris grafts from normal or thyroidectomized hosts reinnervated by matyured locus coeruleus neurons there was no difference in distribution or morphology between the two groups. This clearly shows that matured locus coeruleus neurons are not thyroid hormone dependent during a reinnervation process, after the stimulus elicited by a sensory denervation of iris. When immature locus coeruleus neurons were made to innervate iris grafts by simultaneous grafting of brain tissue and an iris to the eye a clearly reduced number of axon bundles was formed in the iris grafts of the thyroidectomized group. The morphological discrepancies between the two groups were, however, markedly smaller for iris grafts than for corresponding host irides. This might indicate that the potent growth stimulus elicited by sensory denervation of irides partly counteract the inhibition of axon bundle formation by immature grafted locus coeruleus neurons in irides during thyroid hormone deficiency.
将含有蓝斑去甲肾上腺素能神经元的胎儿脑组织块，与经甲状腺切除或正常的宿主大鼠前房内先后或同时移植的虹膜相结合。目的是揭示甲状腺激素缺乏所诱导的、支配虹膜移植片的肾上腺素能纤维可能出现的形态学改变，并将这种可能的激素依赖性与之前在由蓝斑神经元支配的宿主虹膜中所发现的情况进行比较。使用福尔克-希拉尔普荧光组织化学方法，在虹膜整装标本中评估神经纤维的生长情况。在甲状腺切除的宿主中，源自蓝斑的纤维在宿主虹膜上的分布明显改变。荧光轴突束的数量显著减少，且交织的曲张神经纤维丛含有大量荧光物质聚集。在由成熟蓝斑神经元重新支配的正常或甲状腺切除宿主的虹膜移植片中，两组之间在分布或形态上没有差异。这清楚地表明，在虹膜感觉去神经支配引发刺激后，成熟的蓝斑神经元在重新支配过程中不依赖甲状腺激素。当通过将脑组织和虹膜同时移植到眼睛中，使未成熟的蓝斑神经元支配虹膜移植片时，甲状腺切除组的虹膜移植片中形成的轴突束数量明显减少。然而，两组之间在虹膜移植片上的形态差异明显小于相应的宿主虹膜。这可能表明，虹膜感觉去神经支配引发的强大生长刺激，在一定程度上抵消了甲状腺激素缺乏时未成熟移植的蓝斑神经元对虹膜中轴突束形成的抑制作用。
