Fig. 2

Reporting of Risk of Bias assessment of the included studies. The exact questions The following questions were asked: (1) Was the allocation sequence adequately generated and applied? (2) Were the groups similar at baseline or adjusted for confounders? (3) Was the allocation adequately concealed? (4) Were the animals randomly housed during the experiment? (5) Were the caregivers /investigators during the course of the experiment adequately blinded? (6) Were the animals selected at random during outcome assessment? (7) Was the outcome assessment adequately blinded? (8) Were incomplete data outcome adequately addressed? By reporting “yes” we indicated the study as low risk of bias, “no” as high risk of bias, and “unclear” as not reported