Abstract: BACKGROUND: Improving cerebral infarction micromeningeal circulation and inhibiting scar formation can effectively treat cerebral infarction. Therefore, it is very important to develop safe and effective drugs to improve cerebral microcirculation and scar formation.
OBJECTIVE: To investigate the effects of Ratnasampil on pia meningeal microcirculation, Janus kinase 2/signal transducer and activator transcription 3 protein expression and glial scar in rats with cerebral infarction.
METHODS: The 15 of 95 male Sprague-Dawley rats were randomly selected as healthy group and the remaining rats used to establish cerebral infarction models. Five rats died accidentally during the modeling process and the remaining rats were successfully modeled. Model rats were divided into model group, low-dose, medium-dose and high-dose groups of Traditional Chinese medicine and nimodipine group with 15 rats in each group. Low-, medium-and high-dose groups were given 16.67, 33.34 and 66.68 g/kg Ratnasampil suspension once by intragastric administration respectively at 25 minutes before modeling. The nimodipine group was given 30 mg/kg nimodipine tablet once by intragastric administration at 25 minutes before modeling. MCIP microcirculation image processing system was used to detect cerebral blood flow velocity. Hematoxylin-eosin staining was used to observe brain histopathological morphology. Real-time fluorescence quantitative PCR was used to detect gene levels of Janus kinase 2, signal transducer and activator transcription 3, neurocan and glial fibrillary acidic protein. In situ terminal transferase labeling technique was used to measure cell apoptosis. Western blot was used to detect the protein expression of Janus kinase 2, signal transducer and activator transcription 3, phosphorylated signal transducer and activator transcription 3, neurocan and glial fibrillary acidic protein.
RESULTS AND CONCLUSION: Compared with the healthy group, the nimodipine group showed reduced cerebral blood flow velocity, increased expression of Janus kinase 2, signal transducer and activator transcription 3, phosphorylated signal transducer and activator transcription 3, neurocan and glial fibrillary acidic protein, and increased neuronal apoptosis rate at different time points (P < 0.05). Compared with the nimodipine group, the low-dose group showed an increase in cerebral blood flow velocity and a reduction in neuronal apoptosis rate and the expression of Janus kinase 2, signal transducer and activator transcription 3, phosphorylated signal transducer and activator transcription 3, neurocan and glial fibrillary acidic protein (P < 0.05). Compared with the medium-dose group, the high-dose and nimodipine groups showed an increase in cerebral blood flow velocity and a reduction in neuronal apoptosis rate and the expression of Janus kinase 2, signal transducer and activator transcription 3, phosphorylated signal transducer and activator transcription 3, neurocan and glial fibrillary acidic protein (P < 0.05). Compared with the high-dose group, the nimodipine group showed decreased cerebral blood flow velocity, increased neuronal apoptosis rate and elevated expression of Janus kinase 2, signal transducer and activator transcription 3, phosphorylated signal transducer and activator transcription 3, neurocan and glial fibrillary acidic protein at different time points (P < 0.05). The histological structure of the cerebral cortex was normal in the healthy group. In the model group, the number of neurons in the cortex was decreased, some living neurons were pyknotic, and a large number of inflammatory cells were infiltrated. Compared with the model group, these changes were all improved in the low-, medium- and high-dose groups and the nimodipine group, and the high-dose group had a remarkable effect. Overall, these findings suggest that Ratnasampil may affect the formation of glial scar by inhibiting the levels of glial scar marker proteins, including neurocan and glial fibrillary acidic protein, improve the pia meningeal microcirculation, and reduce the apoptosis of brain tissue cells by inhibiting the activation of Janus kinase 2/signal transducer and activator transcription 3 pathway in rats with cerebral infarction, thus playing a role in brain protection.

Key words: Ratnasampil, cerebral infarction rat, pia meningeal microcirculation, JAK2/STAT3, glial scar