Table 2.

Risk of bias.

Study	Sample size calculation	Inclusion and exclusion criteria	Randomization	Allocation concealment	Reporting of animals excluded from analysis	Blinded assessment of outcome	Reporting potential conflicts of interest
Pang et al 2010	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Shangguan et al. 2017	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Li et al. 2014	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Song et al. 2016	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Wang et al. 2015	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Sun et al. 2015	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Li et al. 2013	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Li et al. 2012	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Wang et al. 2016	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No
Zhao et al. 2016	Unclear	Unclear	Yes	Unclear	Unclear	Yes	No