Winner C O
Department of Zoology, Miami University, Oxford, Ohio 45056.
J Exp Zool. 1989 Jan;249(1):23-30. doi: 10.1002/jez.1402490106.
Young blastemas of the newt resorb if the limb is denervated, and are thus called "nerve dependent". Late bud and later stage regenerates are termed "nerve independent" because, while denervation inhibits their growth, they proceed through differentiation to form a normally patterned regenerate. Schotté and Liversage ('59) found that reamputation of a denervated nerve independent regenerate causes it to resorb. The present study asked whether injuries of varying severity are equally effective at promoting resorption. Newt forelimbs were amputated through the mid-radius/ulna. At nerve independent stages, the regenerates were denervated and injured in one of a variety of ways, then monitored for signs of resorption. Reamputation of the tip or incisions which created large gaps in the wound epidermis promoted resorption in 77-90% of the cases. Histology showed that the tissue removed by tip reamputation was a small proportion of the entire regenerate, suggesting that blastema resorption is not determined simply by the number of cells directly affected by the injury. Pin prick injuries, which created small disruptions of the wound epidermis, never caused resorption. Devascularization, caused by severing the brachial artery, promoted resorption in 17% of cases. These results are not consistent with the hypothesis that avascularity is a major causative factor in nerve dependence.
如果蝾螈的肢体去神经支配，其幼芽基会吸收，因此被称为“神经依赖型”。晚期芽体及更后期的再生组织被称为“神经非依赖型”，因为虽然去神经支配会抑制它们的生长，但它们仍会继续分化形成正常模式的再生组织。肖特和利弗萨热（1959年）发现，对去神经支配的神经非依赖型再生组织再次截肢会导致其吸收。本研究探讨了不同严重程度的损伤在促进吸收方面是否同样有效。蝾螈前肢在桡骨/尺骨中部截断。在神经非依赖阶段，对再生组织进行去神经支配，并以多种方式之一进行损伤，然后监测吸收迹象。再次截断尖端或在伤口表皮造成大缺口的切口在77%至90%的病例中促进了吸收。组织学显示，通过再次截断尖端去除的组织仅占整个再生组织的一小部分，这表明芽基吸收并非仅仅由直接受损伤影响的细胞数量决定。针刺损伤仅造成伤口表皮的小破坏，从未导致吸收。切断肱动脉导致的血管去神经支配在17%的病例中促进了吸收。这些结果与无血管是神经依赖的主要致病因素这一假设不一致。
