Table 5.

Risk of bias of the included in vitro studies.

Study	A	B	C	D	E	F	G	H	I	J	Total
He et al., 2014	√			√	√					√	4
Wan et al., 2015	√				√					√	3
Zhou et al., 2016	√	√			√					√	4
Zhou et al., 2017	√	√			√					√	4
Liu, 2018	√	√		√	√					√	5
Meng et al., 2014	√	√		√	√					√	5
Wang, 2016	√	√		√	√					√	5
Wang et al., 2017	√	√		√	√					√	5
Hou et al., 2017	√	√		√	√					√	5
Tu et al., 2018	√	√		√	√					√	5

Studies fulfilling the criteria of: A, peer-reviewed publication; B, use of appropriate primary cells to study; C, cell lines with reliable source or validated by appropriate methods; ,D, assess toxicity of treatment on cells; E, culture environment (culture media/sera, pH/CO₂ and temperature); F, random allocation to treatment or control; G, blinded induction of model; H, blinded assessment of outcome; I, calculation of the sample size necessary to achieve sufficient power; and J, statement of potential conflict of interests. Each item was awarded one point.