In-vitro stress relaxation response of neonatal peripheral nerves
In-vitro stress relaxation response of neonatal peripheral nerves
复制标题
新生儿周围神经的体外应激松弛反应
DOI：
10.1016/j.jbiomech.2021.110702
复制
发表时间：
2021
影响因子：
2.4
通讯作者：
Singh, Anita
中科院分区：
文献类型：
--
作者：
Majmudar, Tanmay;Balasubramanian, Sriram;Magee, Rachel;Gonik, Bernard;Singh, Anita
表征新生儿周围神经的粘弹性行为对于了解新生儿牵张相关周围神经损伤(PNIS)至关重要。本实验研究了新生仔猪臂丛神经和胫神经在两种不同应变水平(10%和20%)和应力松弛测试时间(90秒和300秒)下的体外粘弹性应力松弛反应。采集20头新生仔猪的BP和胫神经，以100 mm/min的动态速率将其预拉伸至10%或20%的应变，以模拟可能导致新生儿伸展相关PNIS的条件，如肩部难产。在恒定应变下，记录的应力降低持续90秒或300秒。然后将生物力学数据拟合到粘弹性模型中，以获得短期和长期应力松弛时间常数。虽然在90秒后，两种神经类型在两种测试应变水平之间的应力松弛程度没有显著差异，但在300秒后，10%应变时的应力降低略大于20%BP时的应力松弛(p=0.056)。在接受300秒测试的神经中，无论是应变水平还是神经类型，压力的减少都明显高于90秒。比较BP和胫神经应力松弛反应，90秒后BP神经松弛程度明显高于胫骨，300秒后差异无统计学意义。我们的结果证实了新生儿周围神经组织是高度粘弹性的。这些新的生物力学数据可以结合到研究新生儿PNIS的有限元和计算模型中。
Characterizing the viscoelastic behavior of neonatal peripheral nerves is critical in understanding stretch-related peripheral nerve injuries (PNIs) in neonates. This study investigated thein-vitroviscoelastic stress relaxation response of neonatal piglet brachial plexus (BP) and tibial nerves at two different strain levels (10% and 20%) and stress relaxation testing durations (90- and 300-seconds). BP and tibial nerves from 20 neonatal piglets were harvested and pre-stretched to either 10% or 20% strain at a dynamic rate of 100 mm/min to simulate conditions, such as shoulder dystocia, that may lead to stretch-related PNIs in neonates. At constant strain, the reduction in stress was recorded for 90- or 300-seconds. The biomechanical data were then fit to a viscoelastic model to acquire the short- and long-term stress relaxation time-constants. Though no significant differences in the degree of stress relaxation were found between the two tested strain levels after 90 seconds in both nerve types, reduction in stress was moderately greater (p = 0.056)at 10% strain than at 20% for BP after 300 seconds. The reduction in stress was significantly higher in nerves subjected to a 300 second testing duration than 90 second for both strain levels and nerve types. When comparing BP and tibial nerve stress relaxation response, BP nerve relaxed significantly more than tibial at both strain levels after 90 seconds, but no significant differences were observed after 300 seconds. Our results confirm that neonatal peripheral nerve tissue is highly viscoelastic. These novel biomechanical data can be incorporated into finite element and computational models studying neonatal PNIs.