Abstract
Abstract in English, French Macrophages provide the first line of defense against Shigella flexneri infection in the gastrointestinal tract by inducing a variety of inflammatory and antimicrobial responses. Secondary metabolites of plants are used as drugs against infections that are resistant to common antibiotics. In this study, the innate effects of asiaticoside on the proinflammatory activity of mouse macrophages infected with S. flexneri were investigated. The viability of the infected mouse macrophages were examined using viability assay, while the pro-inflammatory cytokines productions were determined using the enzyme-linked immunosorbent assay (ELISA) for determination of IL-1β, IL-12 p40 and TNF-α levels. The production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS) protein were determined using the Griess assay and western blot, respectively. Statistical analyses were performed using the Statistical Package of Social Sciences (SPSS) software, version 20. The data obtained from independent experiments (n = 3) were presented as the mean ± standard error of mean (SEM). The results showed that, asiaticoside stimulated the infected macrophages by stimulating increased production of TNF-α, IL-12 p40 and NO as well as increased expression of iNOS in a dose-dependent manner. In contrast the viability of the cells and the production of IL-1β and were reduced also in a dose-dependent manner when compared to untreated cells. These results indicate that asiaticoside has immunomodulatory effects on the innate immune function of infected macrophages, showing the potential use of this compound to reduce the clinical symptoms of the infections. Makrofaj bertindak sebagai sistem pertahanan awal terhadap jangkitan Shigella flexneri di dalam saluran gastrousus (saluran pencernaan) dengan mengaktifkan gerak balas inflamatori dan anti-mikrob. Banyak metabolit sekunder daripada tumbuhan digunakan sebagai agen untuk merawat penyakit yang rintang terhadap antibiotik. Dalam kajian ini, kesan gerak balas semulajadi asiatikosid terhadap aktiviti pro-inflamasi makrofaj mencit yang telah dijangkiti S. flexneri telah dikaji. Kedayahidupan makrofaj mencit dianalisis menggunakan asai kedayahidupan, manakala penghasilan sitokin pro-inflamasi IL-1β, IL-12 p40 dan TNF-α dianalisis menggunakan esei imunoserapan terangkai enzim (ELISA). Penghasilan nitrik oksida (NO) dan pengekspresian protein sintase niktrik oksida teraruh (iNOS) dianalisis menggunakan asai Griess dan analisis pemblotan Western. Analisis statistik dijalankan menggunakan perisian ‘Statistical Package of Social Sciences (SPSS)’ versi 20. Data yang diperolehi daripada eksperimen tak bersandar (n = 3) dibentangkan sebagai min ± min ralat piawai (SEM). Hasil kajian menunjukkan, asiatikosid merangsang pengaktifan makrofaj mencit yang telah dijangkiti melalui peningkatan penghasilan TNF-α, IL12 p40 dan NO serta meningkatkan penghasilan iNOS bergantung kepada dos asiatikosid yang diberikan. Namun begitu, kedayahidupan sel dan penghasilan IL-1β menurun seiring dengan dos yang diberikan dalam sel yang dirawat berbanding dengan sel yang tidak dirawat. Hasil kajian ini menunjukkan bahawa asiatikosid mempunyai kesan imunomodulatori terhadap fungsi imun semulajadi makrofaj yang dijangkiti, yang memberi gambaran potensinya untuk digunakan bagi mengurangkan simptom klinikal jangkitan S. flexneri.