Abstract: Objective  To explore the protection of hydroxysafflor yellow A (HSYA) on the prefrontal cortex nerve cells by observing the microstructure and the inducible nitric oxide synthase expression of the prefrontal cortex neurons of lymphostatic encephalopathy (LE) rats. Methods  A total of 63 Wistar rats were randomly divided into SHAM group, HSYA group and LE group. The rat models of LE and HSYA group were established by ligaturing lymphatic vessels and excising all the superficial and internal cervical lymph nodes. The rats of HSYA group were given hydroxysafflor yellow A after the operation by intraperitoneal injection. The prefrontal cortex brain nerve cells were observed by microscope and electron microscope, and the paraffin sections were used to observe the expression of inducible nitric oxide synthase via immunohistochemical staining. Results  Under optical and electron microscope observation, the nerve cells of prefrontal cortex of LE rats showed irregular morphology, deepened nuclear staining, broken envelop, disappeared nucleolus and fractured myelin. While the SHAM and HSYA group did not show such obvious nerve injuries. The inducible nitric oxide synthase expression increased significantly in the LE group, the highest value appeared in 1d group, and had significant difference compared with 7d and 14d groups (P<0.05). Conclusion  Lymphatic fluid retention induces the magnitude of inducible nitric oxide synthase in the prefrontal cortex nerve cells, which may be associated with the prefrontal cortex neurons  damage. Hydroxysafflor yellow A can restrain the expression of inducible nitric oxide and mitigate the damage.

Key words: Prefrontal cortex,  Lymphostatic encephalopathy, Inducible nitric oxide, Hydroxysafflor yellow A