Table 3.

GRADE assessment for in vitro studies. Overall quality: ++++ high, +++ moderate, ++ low, + very low.

Author	Study Limitations	Inconsistency	Indirectness	Imprecision	Publication Bias	Overall Quality
McGinley (2012) [39]	V	V	V	V	V	++++
Imirzalioglu (2012) [36]	V	V	V	V	V	++++
McGinley (2013) [40]	V	V	V	V	V	++++
Rusu (2014) [41]	X	V	V	X	V	++
Forster(2014) [42]	V	V	V	X	V	+++
Puskar (2015) [44]	V	V	X	X	V	++
Comăneanu (2015) [45]	X	V	V	X	V	++
Gălăţeanu (2016) [46]	V	V	X	V	V	+++
Kim (2016) [24]	V	X	X	V	V	++
Ganbold(2019) [48]	V	V	V	V	V	++++

V, no downgrading; X, one-point downgrading; XX, two-point downgrading.