Liu Yaoqian, Wu Cuiping, Chen Tingting, Shen Qiyue, Xiong Yuanping, Chen Zhengnong, Li Chunyan
Otolaryngology Research Institute Shanghai Jiao Tong University Affiliated Sixth People's Hospital Shanghai China.
Department of Hearing and Language Rehabilitation Zhejiang Chinese Medicine University Hangzhou China.
Laryngoscope Investig Otolaryngol. 2022 Apr 22;7(3):816-824. doi: 10.1002/lio2.797. eCollection 2022 Jun.
To systematically explore the differences in acoustic changes and healing outcomes of tympanic membranes (TMs) with pars flaccida perforation (PFP) and pars tensa perforation (PTP).
We created PFPs and PTPs of various sizes in Sprague-Dawley rats, and evaluated TM umbo velocity and hearing function using laser Doppler vibrometry and auditory brainstem response (ABR) measurement before and immediately after perforation. Two weeks later, hearing was reevaluated and TMs were investigated by immunohistochemical staining.
Small PFPs and PTPs did not significantly affect umbo velocity and hearing function. Large PFPs increased umbo velocity loss at low frequency (1.5 kHz) and elevated ABR thresholds within 1-2 kHz. Large PTP caused significant velocity loss at low frequencies from 1.5 to 3.5 kHz and threshold elevations at full frequencies (1-2 kHz). Two weeks after the perforation, the hearing function of rats with healed PFPs recovered completely. However, high-frequency hearing loss (16-32 kHz) persisted in rats with healed PTPs. Morphological staining revealed that no increase in the thickness and obvious increase in collagen I level of regenerated par flaccida; regenerated pars tensa exhibited obvious increase in thickness and increased collagen I, while the collagen II regeneration was limited with discontinuous and disordered structure in regenerated pars tensa.
The hearing loss caused by large PFP limits at low frequencies while large PTP can lead to hearing loss at wide range frequencies. PFP and PTP have different functional outcomes after spontaneous healing, which is determined by the discrepant structure reconstruction and collagen regeneration.
系统探讨松弛部穿孔（PFP）和紧张部穿孔（PTP）的鼓膜（TM）在声学变化和愈合结果方面的差异。
我们在Sprague-Dawley大鼠中制造了各种大小的PFP和PTP，并在穿孔前和穿孔后立即使用激光多普勒振动测量法和听觉脑干反应（ABR）测量评估TM脐速度和听力功能。两周后，重新评估听力并通过免疫组织化学染色研究TM。
小的PFP和PTP对脐速度和听力功能没有显著影响。大的PFP增加了低频（1.5kHz）时的脐速度损失，并提高了1-2kHz范围内的ABR阈值。大的PTP导致1.5至3.5kHz低频处显著的速度损失以及全频率（1-2kHz）处的阈值升高。穿孔两周后，PFP愈合的大鼠听力功能完全恢复。然而，PTP愈合的大鼠中高频听力损失（16-32kHz）持续存在。形态学染色显示，松弛部再生后厚度没有增加且I型胶原水平没有明显增加；紧张部再生后厚度明显增加且I型胶原增加，而紧张部再生中II型胶原再生有限，结构不连续且紊乱。
大的PFP引起的听力损失局限于低频，而大的PTP可导致广泛频率范围内的听力损失。PFP和PTP在自然愈合后具有不同的功能结果，这由不同的结构重建和胶原再生决定。
