BACKGROUND: Umbilical cord blood-derived mesenchymal stem cells can penetrate the ependyma
into the brain tissue via the systemic circulation, migrate into the injury
area and differentiate into neurons. They are as substitute cells applied in
the treatment of central nervous system diseases
OBJECTIVE: To explore the effects of umbilical
cord blood-derived mesenchymal stem cell transplantation on the functional
recovery of nerve and expression of telomerase reverse transcriptase in the brain
tissue of cerebral infarction rats.
METHODS: One hundred and thirty rats were
enrolled and were randomly divided into control group (n=30), model group (n=30),
umbilical cord blood-derived mesenchymal stem cell 1 group (n=35) and umbilical cord blood-derived
mesenchymal stem cell 2 group (n=35).
The control group was not given any treatment. The rat models of cerebral
infarction were made by internal carotid artery suture method in the other
groups. At 1 and 4 days after successful modeling, 2×106 umbilical
cord blood-derived mesenchymal stem cells were transplanted into tail vein in
the umbilical cord blood-derived mesenchymal stem cell 1 and 2 groups. The
levels of reactive oxygen species and superoxide dismutase were detected at 24
hours after transplantation. The nerve function score was detected by Y-maze
test at 7 and 14 days after transplantation. The neuronal apoptosis in the
center of lesions was detected by TUNEL assay. The expression levels of
Caspase-3, Bax, Bcl-2 and telomerase reverse transcriptase proteins around the
infarct lesion were detected by western blot assay. The mRNA expression of
telomerase reverse transcriptase around infarct lesions was detected by RT-PCR.
RESULTS AND CONCLUSION: Compared with the
control group, in the model group, the error number in the Y-maze test, nerve
function scores, apoptotic index, expression levels of Caspase-3 and Bax, and
level of reactive oxygen species were significantly increased (P < 0.05), the expression of Bcl-2 and
telomerase reverse transcriptase protein and mRNA, and level of superoxide
dismutase were significantly decreased (P < 0.05). Compared with the model group, in the umbilical cord blood-derived
mesenchymal stem cell 1 and 2 groups, the error number in the Y-maze test,
nerve function score, apoptotic index, expression of Caspase-3 and Bax, and
level of reactive oxygen species were significantly decreased (P < 0.05), while the expression of Bcl-2
and telomerase reverse transcriptase protein and mRNA and level of superoxide
dismutase were significantly increased (P < 0.05). Compared with the umbilical cord blood-derived mesenchymal stem
cell 2 group, in the umbilical cord blood-derived mesenchymal stem cell 1
group, the error number in the Y-maze test, nerve function score, apoptotic
index, expression of Caspase-3 and Bax, and level of reactive oxygen species
were significantly decreased (P <
0.05), while the expression of Bcl-2 and telomerase reverse transcriptase
protein and mRNA and level of superoxide dismutase were significantly increased
(P < 0.05). These findings
indicate that umbilical cord blood-derived mesenchymal stem cell
transplantation can effectively promote the neurological recovery in rats with
cerebral infarction, and up-regulate the expression of telomerase reverse
transcriptase in rat brain tissue. Moreover, earlier cell transplantation
indicates better effects.