OBJECTIVETo explore the effects of umbilical cord blood mononuclear cells (UCBMC) transplantation on the neuronal apoptosis and the expression of Bcl-2 and Bax proteins in neonatal rats with hypoxic-ischemic brain damage (HIBD).

METHODSSeven-day-old Sprague-Dawley neonatal rats were randomly divided into normal control (N)+normal saline (NS), HIBD+NS, N+UCBMC, and HIBD+UCBMC groups. HIBD model was prepared using the classical Rice-Vannucci method. Twenty-four hours after HIBD, UCBMC were transplanted in the N+UCBMC and HIBD+UCBMC groups. Seven days after transplantation, NeuN/Cleaved-Caspase-3 double immunofluorescence staining and TUNEL methods were used to observe neural apoptosis in the cortex. The expression levels of Bax and Bcl-2 proteins were examined by Western blot analysis.

RESULTSThere were more NeuNcleaved Caspase-3DAPIand TUNELDAPIcells in the HIBD+NS group compared with the N+NS and N+UCBMC groups (P<0.01). There were less NeuNcleaved Caspase-3DAPIand TUNELDAPIcells in the HIBD+UCBMC group compared with the HIBD+NS group (P<0.01). The concentration of Bax protein was higher and that of Bcl-2 proteins was lower in the HIBD+NS group compared with the N+NS and N+UCBMC groups (P<0.01). The concentration of Bax protein in HIBD+UCBMC group was lower than that in the HIBD+NS group (P<0.01). The concentration of Bcl-2 protein was higher compared with the HIBD+NS, N+NS and N+UCBMC groups (P<0.05).

CONCLUSIONSUCBMC transplantation via lateral ventricle can upregulate the expression of Bcl-2 protein and down-regulate the expression of Bax protein, thus alleviating brain neural apoptosis in neonatal rats with HIBD.