Comparsion between Intravenous Delivered Human Fetal Bone Marrow Mesenchymal Stromal Cells and Mononuclear Cells in the Treatment of Rat Cerebral Infarct.

Objective To compare the effecacy of human mesenchymal stromal cell (hMSC) with human mononuclear cell (hMNC) in treating rat cerebral infarct.Methods The SD rat models of cerebral infarct were established by distal middle cerebral artery occlusion (dMCAO). Rats were divided into four groups: sham,ischemia vehicle,MSC,and MNC transplantation groups. For the transplantation group,1×10 hMSCs or hMNCs were intravascularly transplanted into the tail vein 1 hour after the ischemia onset. The ischemia vehicle group received dMCAO surgery and intravascular saline injection 1,3,5,and 7 days after the ischemia onset,and then behavioral tests were performed. At 48 h after the ischemia onset,the abundance of Iba- 1,the symbol of activated microglia,was evaluated in the peri-ischemia striatum area; meanwhile,the neurotrophic factors such as glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) in ipsilateral peri-ischemia striatum area were also measured. Results The relative infarct volume in ischemia vehicle group,hMSC group,and hMNC transplantation group were (37.85±4.40)%,(33.41±3.82)%,and (30.23±3.63)%,respectively. The infarct volumes of MSC group (t=2.100,P=0.034) and MNC group (t=2.109,P=0.0009) were significantly smaller than that of ischemia vehicle group,and that of MNC group was significantly smaller than that of MSC group (t=1.743,P=0.043). One day after transplantation,the score of ischemia vehicle group in limb placing test was (4.32±0.71)%,which was significantly lower than that in sham group (9.73±0.36)% (t=2.178,P=8.61×10). The scores of MSC and MNC group,which were (5.09±0.62)% (t=2.1009,P=0.024) and (5.90±0.68)% (t=2.1008,P=0.0001),respectively,were significantly higher than that of ischemia vehicle group; also,the score of MNC group was significantly higher than that of MSC group(t=2.1009,P=0.0165). The contralateral forelimb scores of MSC and MNC groups in beam walking test were (5.56±0.86)% (t=2.120,P=0.020) and (5.13±0.95)% (t=2.131,P=0.003),were both significantly lower than that of ischemia vehicle group [(6.47±0.61)%]. Three days after the transplantation,the limb placing test score of MNC group [(6.91±1.10)%] was significantly higher than that of ischemia vehicle group (5.80±0.82)% (t=2.110,P=0.027). The score of MSC group [(6.30±0.77)%] showed no statistic difference with that of ischemia vehicle group(t=2.101,P=0.199).The contralateral forelimb scores of MNC group in beam walking test [(4.34±0.58)%] was significantly lower than that of ischemia vehicle group [(5.31±0.65)%] (t=2.100,P=0.006) and MSC group [(4.92±0.53)%] (t=2.100,P=0.041); there was no statistic difference between MSC group and ischemia vehicle group (t=2.109,P=0.139). The relative abundance of Iba- 1 in sham,ischemia vehicle,MSC,and MNC groups was 1.00+0.00,1.72±0.21,1.23±0.08,and 1.48±0.06,respectively. The Iba-1 relative abundance of ischemia vehicle group was significantly higher than that of sham group (t=2.262,P=2.9×10). The Iba-1 relative abundances of both MSC (t=2.178,P=3.91×10)and MNC (t=2.200,P=0.007)groups were significantly lower than that of ischemia vehicle group. It was also significantly lower in MNC group than in MSC group also (t=2.120,P=7.09×10). Three days after transplantation,the BDNF and GDNF levels of MSC group,which were (531.127±73.176)pg/mg (t=2.109,P=0.003)and(127.780±16.733)pg/mg(t=2.100,P=2.76×10),respectively,were significantly higher than those of ischemia vehicle group,which were (401.988±89.006)pg/mg and (86.278±14.832) pg/mg,respectively. The BDNF and GDNF levels of MNC group,which were (627.429±65.646)pg/mg (t=2.144,P=0.017) and (153.117±20.443)pg/mg (t=2.109,P=0.010),respectively,were all significantly higher than that of MSC group. At day 7,the BDNF and GDNF levels of MSC group,which were (504.776±83.282)pg/mg (t=2.101,P=0.005) and (81.641±11.019)pg/mg (t=2.100,P=0.002),respectively,were significantly higher than those of ischemia vehicle group,which were (389.257±70.440)pg/mg and (64.322±9.855) pg/mg,respectively. The BDNF and GDNF levels of MNC group,which were (589.068±63.323)pg/mg (t=2.100,P=0.027) and (102.161±19.932)pg/mg (t=2.144,P=0.017),respectively,were all significantly higher than that of MSC group. Conclusions Both hMSC and hMNC are beneficial to the ischemia-damaged brain when they are intravascularly transplanted within 1 h after the onset of ischemia. The anti-inflammation ability and secretion of neurotrophic factors are the underlying mechanisms of the therapeutic effects. MNC is more effective than MSC in reducing infarct area and improving behaviors,which might be explained by the fact that MNC induces more GDNF and BDNF in brain than MSC.