Effect of G-CSF and TPO on HIBD in neonatal rats

To observe effect of granulocyte colony-stimulating factor (G-CSF) and restructure human thrombopoietin on hypoxic-ischemic brain damage (HIBD) in new born rats.

A total of 60 neonatal SD rats were selected and divided into 4 groups, with 15 in each group. Group A served as control group. Rats of Groups B-D were prepared for HIBD model by ligation of left common carotid artery combined with hypoxia method. Rats of Group A were only completed with free left common carotid artery without ligation and hypoxia operation. After HIBD model preparation, Group B was administrated with subcutaneous injection of normal saline for placebo treatment; Group C was administrated with cervical subcutaneous injection of 0.5 μg/10 g granulocyte colony stimulating factor (G-CSF) for 5 d (Once a day); Group D was administrated with intraperitoneal injection of 15 U/10 g recombinant human thromobopoietin (rhTPO) for treatment. After modeling for 7, 14 and 21 d, 5 rats were sacrificed in each group, respectively. Brain quality damage (%) conditions of experimental animals in each group were compared in different time points, and cerebral histopathological changes of each group were observed. Expression of nestin in rats of each group was detected by immunohistochemical method.

After modeling for 7, 14 and 21 d, brain quality damages (%) of Groups B, C and D were significant higher than that of in Group A (P<0.05), while brain quality damage (%) degree of Group B was the highest in different time points, followed by Groups D and C, respectively. It was significant different compared among groups (P<0.05). The histopathological observation showed that degrees of brain damages in Groups C and D were significant lower than that of in Group B. After modeling for 7, 14 and 21 d, nestin positive cell populations in Groups B, C, and D were significant higher than Group A (P<0.05). Nestin cell populations of Group C in different time points were significant higher than Groups B and D (P<0.05). There was no significant difference in nestin positive cell populations in the above time points between Groups B and D (P>0.05).

Both G-CSF and TPO can protect the nervous system of HIBD neonatal rats. G-CSF can promote the proliferation and differentiation of neural precursor cells to decrease the degeneration and necrosis of nerve cell. TPO can obviously ameliorate morphology index of HIBD rats. Through regulating ratio of TIMP-1 and MMP-9, TPO can maintain the integrity of blood brain barrier to relieve the occurrence of brain damage.