Table 2.

Risk of bias of the included studies.

	1	2	3	4	5	6	7	8	9	10
Zhang [24]	U	Y	U	Y	U	U	U	Y	Y	U
Zhang [25]	U	U	U	Y	U	U	U	Y	Y	U
Yang and Cheng [26]	U	U	U	U	U	U	U	Y	Y	U
Qin and Yan [27]	U	U	U	U	U	U	U	Y	Y	U
Sun et al. [28]	U	U	U	U	U	U	U	Y	Y	U
Liu et al. [29]	U	U	U	U	U	U	U	N	Y	U
Guo [30]	U	Y	U	U	U	U	U	N	Y	U
Bai [31]	U	Y	U	Y	U	U	U	U	Y	U
Zhang [32]	U	U	U	U	U	U	U	N	Y	U
Shu et al. [33]	U	U	U	Y	U	U	U	U	Y	U
Meng et al. [34]	U	U	U	U	U	U	U	Y	Y	U

Y, yes; N, no; U, unclear; (1) whether the allocation sequence adequately generated and applied; (2) whether the baselines are identical; (3) whether the allocation adequately concealed; (4) whether the animals were randomly placed during the experiment; (5) whether researchers were blinded; (6) whether the animals were selected at random for outcome assessment; (7) whether results evaluators are blinded; (8) whether incomplete data are reported; (9) whether the research report is irrelevant to the selective results report; (10) whether there is no other bias.