Microfluidic Chip and Flow Cytometry for Examination of the Antiplatelet Effect of Ticagrelor / 中国医学科学院学报

Objective To examine the antiplatelet effect of ticagrelor by microfluidic chip and flow cytometry under shear stress in vitro. Methods Microfluidic chip was used to examine the effect of ticagrelor on platelet aggregation at the shear rates of 300/s and 1500/s.We adopted the surface coverage of platelet aggregation to calculate the half inhibition rate of ticagrelor.The inhibitory effect of ticagrelor on ADP-induced platelet aggregation was verified by optical turbidimetry.Microfluidic chip was used to construct an in vitro vascular stenosis model,with which the platelet reactivity under high shear rate was determined.Furthermore,the effect of ticagrelor on the expression of fibrinogen receptor (PAC-1) and P-selectin (CD62P) on platelet membrane activated by high shear rate was analyzed by flow cytometry. Results At the shear rates of 300/s and 1500/s,ticagrelor inhibited platelet aggregation in a concentration-dependent manner,and the inhibition at 300/s was stronger than that at 1500/s (both P<0.001).Ticagrelor at a concentration ≥4 μmol/L almost completely inhibited platelet aggregation.The inhibition of ADP-induced platelet aggregation by ticagrelor was similar to the results under flow conditions and also in a concentration-dependent manner.Ticagrelor inhibited the expression of PAC-1 and CD62P. Conclusion We employed microfluidic chip to analyze platelet aggregation and flow cytometry to detect platelet activation,which can reveal the responses of different patients to ticagrelor.

Investigation of the protective effect of enoxaparin and ticagrelor pretreatment against ischemia-reperfusion injury in rat lung tissue

SUMMARY OBJECTIVES This study was conducted to reveal the possible protective effects of ticagrelor and enoxaparin pretreatment against ischemia-reperfusion (IR)-induced injury on the lung tissue of a rat model. METHODS Wistar albino rats were randomly divided into 4 groups as follows: group-1 (control-sham), group-2 (control-saline+IR), group-3 (ticagrelor+IR), group-4 (enoxaparin+IR). Before the ischemic period, saline, ticagrelor, and enoxaparin were administered to the 2nd-4th groups, respectively. In these groups, IR injury was induced by clamping the aorta infrarenally for 2 h, followed by 4 h of reperfusion except group-1. After the rats were euthanized, the lungs were processed for histological examinations. Paraffin sections were stained with Haematoxylin&Eosin (H&E) for light microscopic observation. Apoptosis was evaluated by caspase-3 immunoreactivity. Data were statistically analyzed using the SPSS software. RESULTS In the lung sections stained with H&E, a normal histological structure was observed in group-1, whereas disorganized epithelial cells, hemorrhage, and inflammatory cell infiltration were seen in the alveolar wall in group-2. The histologic structure of the treatment groups was better than that of group-2. Caspase-3(+) apoptotic cells were noticeable in sections of group-2 and were lower in the treatment groups. In group-4, caspase-3 immunostaining was lower than in group-3. In group-2, apoptotic cells were significantly higher than in the other groups (p<0.001). CONCLUSION Based on the histological results, we suggested that both therapies ameliorated the detrimental effects of IR. Caspase-3 immunohistochemistry results also revealed that pre-treatment with enoxaparin gave better results in an IR-induced rat injury model. In further studies, other parameters such as ROS and inflammatory gene expressions should be evaluated for accurate results.

RESUMO OBJETIVOS Este estudo foi realizado para revelar os possíveis efeitos protetores do ticagrelor e do pré-tratamento da enoxaparina no tecido pulmonar contra o modelo de lesão induzida por isquemia-reperfusão (IR). MÉTODOS Ratos albinos Wistar foram randomizados e divididos em quatro grupos: grupo 1 (controle-sham), grupo 2 (controle-salina + IR), grupo 3 (ticagrelor + IR), grupo 4 (enoxaparina + IR). Antes do período isquêmico, salina, ticagrelor e enoxaparina foram administrados nos grupos 2-4, respectivamente. Nesses grupos, a lesão de IR foi induzida pelo clampeamento da aorta na região da infrarrenal por duas horas, seguida por quatro horas de reperfusão, exceto no grupo 1. Após a sacrificação, os pulmões foram processados para exames histológicos. Secções de parafina foram coradas com hematoxilina e eosina (H&E) para observação microscópica de luz. A apoptose foi avaliada pela imunorreatividade da caspase-3. Os dados foram analisados estatisticamente pelo programa SPSS. RESULTADOS Nas secções pulmonares coradas com H&E, estrutura histológica normal foi observada no grupo 1, enquanto células epiteliais desorganizadas, hemorragia e infiltração de células inflamatórias foram observadas na parede alveolar no grupo 2. A estrutura histológica dos grupos de tratamento foi melhor que o grupo 2. Células apoptóticas caspase-3 (+) foram notadas em secções do grupo 2, e essas células foram mais baixas nos grupos de tratamento. No grupo 4, a imunocoloração com caspase-3 foi menor que no grupo 3. No grupo 2, as células apoptóticas foram significativamente maiores que nos outros grupos (p<0,001). CONCLUSÃO Com base nos resultados histológicos, sugerimos que ambas as terapias atenuaram os efeitos prejudiciais da RI. Resultados de imuno-histoquímica com caspase-3 também revelaram que o pré-tratamento com enoxaparina proporcionou melhores resultados no modelo de lesão induzida por IR. Em estudos posteriores, outros parâmetros, como ROS e expressões gênicas inflamatórias, devem ser avaliados quanto a resultados precisos.