Perbandingan Ekspresi mRNA Bax, mRNA Bcl-2, Rasio mRNA Bax/Bcl-2, dan Indeks Apoptosis Sel Trofoblas antara Plasenta Akreta Spektrum dan Kehamilan Normal di RSUP Dr Sardjito

DEYNA PRIMAVITA PAHLEVI, dr. Ahsanudin Attamimi, SpOG(K)-KFM, MMedED; dr. Didik Setyo Heriyanto, PhD., SpPA(K).Subsp.Kv.R.M.(K)

2023 | Tesis-Subspesialis | SUBSPESIALIS OBSTETRI DAN GINEKOLOGI

Latar Belakang: Meningkatnya angka kasus plasenta akreta spektrum dan etiologinya diduga disebabkan oleh defek pada interface endometrium-miometrium, yang mengakibatkan kegagalan desidualisasi normal pada area luka rahim sebelumnya. Hal ini memungkinkan infiltrasi trofoblas dan vili korialis plasenta secara abnormal lebih dalam ke dalam miometrium, ditandai oleh invasi yang lebih dalam oleh jaringan sitotrofoblas. Diperkirakan bahwa terjadi penurunan apoptosis sitotrofoblas pada kondisi ini. Gen keluarga Bcl-2 memainkan peran penting dalam regulasi apoptosis pada plasenta akreta spektrum. Lebih lanjut, rasio ekspresi BAX (pro-apoptosis) terhadap Bcl-2 (anti-apoptosis) menentukan kerentanan sel terhadap apoptosis. Peneliti akan mengkaji perbedaan ekspresi gen keluarga BCL-2, yaitu BAX dan Bcl-2, pada tingkat messenger RNA (mRNA) dan perbedaan ekspresi fragmentasi DNA sebagai indikator indeks apoptosis antara pasien plasenta akreta spektrum dan kehamilan normal.

Metode Penelitian: Penelitian ini adalah studi analitik cross-sectional yang menggunakan sampel plasenta Formalin-fixed, paraffin-embedded (FFPE) dari kelompok plasenta akreta spektrum dan kehamilan normal. Ekstraksi mRNA dilakukan pada sampel masing-masing kelompok, diikuti oleh penilaian ekspresi mRNA BAX dan Bcl-2 dengan RT-qPCR, perhitungan rasio ekspresi mRNA BAX/Bcl-2, dan pemeriksaan fragmentasi DNA menggunakan LM-RT-PCR.

Hasil Penelitian: Rerata fold change mRNA BAX PAS lebih rendah dibandingkan kehamilan normal (3,61 ± 2,61 vs. 11,75 ± 10,66 p=0,0016). Rerata fold change mRNA Bcl-2 PAS lebih tinggi dibandingkan kehamilan normal (35,95 ± 28,98 vs. 5,50 ± 3,05 p=0,00131). Rasio fold change BAX/Bcl-2 PAS lebih rendah dibandingkan kehamilan normal (0,16 ± 0,12 vs 3,43 ± 4,43 p=0,001). Rerata cycle threshold (CT) fragmentasi DNA PAS lebih tinggi dibandingkan kehamilan normal (33,78 ± 1,12 vs 28,40 ± 0,69 5,38 p=0,001). Terdapat korelasi yang signifikan antara antara ekspresi mRNA Bcl-2 dan indeks apoptosis dengan arah korelasi positif dan koefisien korelasi sedang yakni 0,415 dan p = 0,023. Terdapat hubungan antara ekspresi mRNA BAX, Bcl-2, rasio ekspresi BAX/Bcl-2, dan indeks apoptosis sel trofoblas pada kedua kelompok, plasenta akreta spektrum dan kehamilan normal. Rasio BAX/Bcl-2 meningkat menunjukkan bahwa penanda proapoptosis lebih dominan daripada antiapoptosis.

Kesimpulan: Pada plasenta akreta spektrum, ekpresi mRNA BAX dan rasio BAX/bcl-2 lebih rendah secara signifikan tetapi pada Bcl-2 dan indeks apoptosis meningkat secara signifikan dibandingkan pada subjek plasenta normal serta didapatkan korelasi signifikan antara Bcl-2 dan indeks apoptosis.

Background: The increasing number of cases of placenta accreta and its aetiology are suspected to be caused by defects in the endometrial-myometrial interface, which fails normal decidualization in previous uterine injury. This allows infiltration of trophoblast and placental chorionic villi abnormally deeper into the myometrium, characterized by deeper invasion by cytotrophoblast tissue. It is thought that there is a decrease in cytotrophoblast apoptosis in this condition. BCL-2 family genes are essential in regulating apoptosis in the placenta accreta spectrum. Furthermore, the expression ratio of BAX (pro apoptosis) to Bcl-2 (anti-apoptotic) determines the susceptibility of cells to apoptosis. Researchers will examine the differences in gene expression of the BCL-2 family, namely BAX and Bcl-2, at the messenger RNA (mRNA) level and differences in the expression of DNA fragmentation as an indicator of the apoptosis index between patients with placenta accreta spectrum and normal pregnancies.

Methods: This cross-sectional analytic study used Formalin-fixed, paraffin-embedded (FFPE) placenta samples from the placenta accreta spectrum and normal pregnancy groups. mRNA extraction was performed on samples from each group, followed by an assessment of BAX and Bcl-2 mRNA expression by RT-qPCR, calculation of the BAX/Bcl-2 mRNA expression ratio, and examination of DNA fragmentation using LM-RT-PCR.

Results: The average fold of changes in mRNA BAX is lower than in normal pregnancy (3.61 ± 2.61 vs 11.75 ± 10.66 p= 0.0016). The middle fold of changes in mRNA BCL-2 PAS is higher than in normal pregnancy (35.95 ± 28.98 vs 5.50 ± 3.05 p= 0.00131). Ratio Changes in BAX/BCl-2 PAS are lower than in normal pregnancy (0.16 ± 0.12 vs 3.43 ± 4.43 p = 0.001). The average Cycle Threshold (CT) Fragmentation of DNA PAS is more than in normal pregnancy (33.78 ± 1.12 vs 28.40 ± 0.69 p= 0.001). There is a significant correlation between the expression of BCL-2 mRNA and the Apoptosis index of the positive correlation direction and the moderate correlation coefficient of 0.415 and P = 0.023. There is a relationship between BAX, BCL-2 mRNA expressions, BAX/BCL-2 expression ratios, and trophoblast cell apoptosis indexes in both groups, placenta accreta spectrum, and normal pregnancy. The ratio of BAX/BCL-2 increases shows that pro apoptotic markers are more dominant than anti apoptotic.

Conclusion: In the placenta accreta spectrum, BAX mRNA expression and BAX/bcl-2 ratio was significantly lower, but Bcl-2 and the apoptotic index increased particularly compared to normal placental subjects, and a significant correlation was found between Bcl-2 and the apoptotic index.

Kata Kunci : mRNA, BAX, BCL-2, Indeks Apoptosis, Fragmentasi DNA, Plasenta akreta spektrum