Effect of exosomes derived from adipose-derived mesenchymal stem cells on neuron apoptosis and inflammatory

Objective To investigate the effect of exosomes derived from adipose-derived mesenchymal stem cells (ADMSCs) on neuron apoptosis and inflammatory cytokines in cerebral ischemia reperfusion (I/R) mice. Methods ADMSCs were extracted from adipose tissue adjacent to the epididymis in 10 8-week-old healthy male SD rats, and the cells of the third generation were cultured under normal oxygen (21%) and hypoxia (1%) conditions, respectively. After 24 h, the culture supernatant was collected and exosomes were separated by kit extraction method. Sixty 8-week-old healthy male SD rats were randomly divided into 5 groups, that is, sham-operation group, I/R group, PBS group, hypoxic exosomes group, and normoxic exosomes group (n=12). Rat model of cerebral I/R was established by insertion of a thread through the internal carotid artery in the latter 4 groups. The rats of PBS group were injected intraperitoneally with 2 mL PBS, while those of the hypoxic and normoxic exosomes groups were given 100 μg of hypoxic and normoxic exosomes, respectively. In 24 h after cerebral I/R injury, neurological function was evaluated by Longa score, infarct volumes were measured by TTC staining, neuronal apoptosis was detected by TUNEL assay, the expression of cytochrome C (CytC) and interleukin-1β (IL-1β) was detected by immunohistochemical staining. HE staining was employed to observe the morphological changes of the injury. Results Compared with the PBS group, the hypoxic and normoxic exosomes groups demonstrated significant decreases in pathological changes, neurological functional score, percentage of infarct volumes, expression levels of Cyt C and IL-1β, and neuronal apoptosis index (P < 0.05). While, the decreases were more significant in the hypoxic than the normoxic exosomes group (P < 0.05). Conclusion ADMSCs-derived exosomes can reduce the apoptosis of neurons and the expression of IL-1β after cerebral I/R injury and show neuroprotective effects, which may be due to exosomes' inhibition of mitochondrial-mediated apoptosis and IL-1β-involved inflammatory cascade reactions