OBJECTIVETo study the influence of conditioned medium of rat brain microvascular endothelial cells on mitochondrial function of cortical neurons and the protective effect of Tongluo Jiunao Injection (TJI) on it.

METHODSFour kinds of conditioned endothelial cell (EC) cultured medium were prepared, i.e. the N-CM medium prepared by EC cultured in the normal conditioned medium without any treatment; the NT-CM prepared by EC cultured in N-CM and treated with TJI 1 microl/ml for 10 h; the I-CM prepared by EC cultured in the non-glucose kreb medium under hypoxia condition; and the IT-CM by EC pre-treatce with TJI 1 microl/ml for 4 h and cultured as that of I-CM. The levels of neuronic mitochondrial activity, membrane potential (MMP) and cytochrome C (Cyt C) were determined before and after the glucose-oxygen deprived model neurons of brain cortex being cultured with different kinds of conditioned EC cultured medium for assessing the effects of these media on mitochondria of injured neuron.

RESULTSAs compared with those of the normal neuron, the mitochondrial activity and MMP of all injured neurons decreased and Cyt C level increased significantly. But comparison of these indexes among neurons cultured with different conditioned EC culture media showed that the greatest extent abnormality revealed in the N-CM cultured neurons, which even greater than that in the model neuron; while that was less in the N-CM cutured neuron than in model neuron; as for those cultured in the NT-CM and IT-CM, i.e. the TJI treated cuture medium, the abnormal changes were reduced significantly when compared with those cultured in medium untreated with TJI (N-CM and I-CM), respectively (all P < 0.05).

CONCLUSIONThe paracrine secretion of the brain microvascular endothelial cells has evident regulatory effect on survival of the injured neurons, which might possibly be related to its protective effect on neuron mitochondrial function, and TJI could enhance the protective effect.