TABLE 2.

Experimental parameters and outcomes of in vitro studies investigating the role of LIU on Schwann cells in vitro.

Study	Therapeutic regiment					Cells		Outcomes
	Transducer	Parameters	Application	Duration	Length	Cell culture	Number	Proliferation	Apoptosis	Gene regulation
Zhang et al., 2009	Bottom of the plate	100 mW/cm2, 1 Mhz, 20% pulsed	Every day	5 min	14 days	Primary rat SC	3.000/cm2	Increased at day 4, 7 and 10	n.d.	Increased NT3 expression and decreased BDNF expression at day 14 (RT-PCR)
Tsuang et al., 2011	Immersed	300 mW/cm2, 1 Mhz, 20% pulsed	Once	2 min	2 days	Primary rat SC	2.000/cm2	Increased at day 2	Decreased at day 1	n.d.
Yue et al., 2016	Bottom of the plate	20 mW/cm2, 1 Mhz, 20% pulsed	Every day	10 min	7 days	Rat SC RSC96	60.000/cm2	n.d.	n.d.	Increased ErbB3, NRG1, EGR2 and MBP expression at day 1, 4 and 7 (qPCR)
Ren et al., 2018	Bottom of the plate	27.500 mW/cm2†	Every day	10 min	5 days	primary rat SC	2.000/cm2	Increased at day 5	n.d.	Increased FDF, NGF, BDNF, GDNF, p-GSK-3β, β-catenin expression at day 5 (WB)

Listed are the key elements of all analyzed studies including therapeutic regimen, cell type and number and major outcomes on Schwann cell proliferation, apoptosis, and gene expression. †, Ren et al. (2018) reported using an intensity of 27.5 W/cm², which is considered high intensity ultrasound. For this table, we use the PRISMA 2020 guidelines for systematic review (Page et al., 2021) and identified 4 reports. SC, Schwann cell. n.d., not determined. qPCR, quantitative PCR. RT-PCR, reverse transcriptase PCR. WB, western blot.