Table 1. Assessment of risk of bias in the included studies.

Bias	Item Number	Question	Li [21]	Liu [22]	Wang [23]	Li [24]	Du et al. [25]	Li et al. [26]	Li et al. [27]	Liu et al. [28]	Liu et al. [29]	Du et al. [30]
Randomization	1	Were animals randomized across groups?	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y
	2	What method was used for randomization?	Y	U	U	U	U	Y	Y	U	U	U
Blindness	3	Was the outcome assessment blinded?	U	U	U	U	U	U	U	U	U	U
Experimental animals	4	Were characteristics of experimental animals clearly described?	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y
Baseline	5	Were the groups similar at baseline?	Y	Y	Y	Y	U	Y	Y	Y	Y	Y
Homogeneity	6	Was each treatment homogeneous?	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y
	7	Was the method of outcome measurement proper and homogeneous?	Y	Y	Y	Y	Y	Y	Y	Y	Y	Y
Data completion	8	Was the number of animals excluded from analysis and the reason for exclusion clear?	U	U	U	U	U	U	U	U	U	U
	9	Were the outcome data complete?	Y	Y	N	Y	Y	Y	Y	Y	Y	Y

Y, yes; N, no description; U, unclear description.