Table 5 The results of stratified meta-analysis
Subgroups | Acquisition memory | Retention memory | ||||||
|---|---|---|---|---|---|---|---|---|
Studies | Participants | Effect size, 95 % CI | Studies | Participants | Effect size , 95 % CI | |||
Gensenosides | ||||||||
Rb | 2 | 56 | −2.21 [−2.90, −1.53] | P < 0.00001 | ||||
Rg1 | 13 | 290 | −2.86 [−3.83, −1.90] | 9 | 200 | 3.52 [1.95, 5.09] | P = 0.01 | |
Rg2 | 3 | 72 | −1.31 [−1.82, −0.79] | 4 | 88 | 1.40 [−0.84, 1.97] | ||
Rg3 | 3 | 36 | −2.56 [−4.42, −0.71] | |||||
Rg5 | 3 | 72 | −0.46 [−0.96, 0.04] | |||||
Dose | ||||||||
1–9 mg | 9 | 216 | −1.287 [−1.92, −0.62] | P = 0.009 | 7 | 172 | 1.17 [0.42, 1.93] | P = 0.002 |
10 mg | 9 | 206 | −2.54 [−3.49, −1.59] | 3 | 60 | 6.54 [1.97, 11.1] | ||
20 mg | 5 | 92 | −2.90 [−4.51, −1.28] | 3 | 56 | 4.30 [2.22, 6.37] | ||
30 mg | 1 | 12 | −4.81 [−7.41, 2.20] | |||||
Animal species | ||||||||
Mouse | 6 | 136 | −1.21 [−1.87, −0.55] | P = 0.008 | 4 | 96 | 1.35 [0.34,2.35] | P = 0.002 |
Rat | 18 | 390 | −2.52 [−3.24, −1.80] | 9 | 192 | 3.52 [2.02,5.01] | ||
Gender | ||||||||
Male | 11 | 258 | −2.65 [−3.66, −1.63] | P = 0.0008 | 5 | 256 | 3.22 [1.66, 6.26] | P = 0.003 |
Female | 5 | 84 | −3.42 [−4.84, −2.00] | 5 | 84 | 3.78 [1.38, 6.10] | ||
Mixed | 3 | 72 | −1.31 [−1.82, −0.79] | 3 | 73 | 1.22 [0.70, 1.73] | ||
Unclear | 5 | 112 | −0.86 [−1.46, −0.26] | |||||
Anesthetic agent | ||||||||
Pentobarbital | 4 | 52 | −2.22 [−3.40, −1.05] | P = 0.06 | 1 | 16 | 2.53 [1.13, 3.94] | P = 0.87 |
Chloral hydrate | 14 | 322 | −2.66 [−3.52, −1.80] | 12 | 272 | 2.68 [1.63, 3.72] | ||
Ether | 2 | 40 | −1.58 [−2.32, −0.85] | |||||
Unclear | 4 | 112 | −0.95 [−1.96, 0.06] | |||||
Drug delivery | ||||||||
ip | 17 | 366 | −2.23 [−2.87, −1.58] | P = 0.68 | 9 | 200 | 1.61 [0.73, 2.49] | P = 0.002 |
0r | 7 | 160 | −1.95 [−3.09, −0.81] | 4 | 88 | 4.50 [2.92, 6.08] | ||
Study quality | ||||||||
4 | 2 | 50 | −4.05 [−8.02, −0.08] | P < 0.00001 | 1 | 20 | 2.36 [1.16, 3.56] | P < 0.001 |
5 | 3 | 72 | −1.31 [−1.82, −0.79] | 6 | 132 | 1.22 [2.92, 6.08] | ||
6 | 11 | 260 | −1.90 [−2.63, −1.17] | 4 | 88 | 4.50 [2.92, 6.08] | ||
7 | 2 | 60 | −0.36 [−0.87, 0.15] | 6 | 124 | 0.52 [0.00, 1.03] | ||
8 | 6 | 84 | −3.66 [−5.20, −2.13] | 3 | 48 | 5.98 [−0.63, 12.59] | ||