Pengaruh Allopurinol terhadap Ekspresi mRNA Toll-Like Receptor 4 (TLR4) dan Monocyte Chemoattractant Protein 1 (MCP-1) pada Jantung Mencit yang Diinduksi Asam Urat

GRATCHEVA ALEXANDRA, dr. Nur Arfian, Ph.D; Dr. dr. Dwi Cahyani Ratna Sari, MKes., PA(K)

2019 | Skripsi | S1 KEDOKTERAN

Latar Belakang: Peningkatan kadar asam urat berkaitan dengan kejadian penyakit jantung. Asam urat mampu memacu respon inflamasi pada organ lain (ginjal dan sendi) melalui aktivasi TLR4, dan menginduksi pelepasan sitokin pro-inflamasi, salah satunya MCP-1. Namun, pengaruh asam urat pada TLR4 dan MCP-1 pada jantung belum diketahui. Allopurinol mampu menurunkan kadar asam urat, namun, pengaruhnya pada inflamasi jantung belum diketahui secara jelas. Tujuan: Mengkaji efek pemberian allopurinol terhadap inflamasi jantung yang dinilai dengan ekspresi mRNA MCP-1 (Monocyte Chemoattractant Protein 1) dan TLR4 (Toll-Like Receptor 4). Metode: Dua puluh lima ekor mencit galur Swiss-Webster (3 bulan, 30-40 gram) dibagi menjadi 5 kelompok: kontrol, pemberian asam urat selama 7 hari (AU7), pemberian asam urat selama 14 hari (AU14), AU7 + allopurinol 7 hari (ALU7), dan AU14 + allopurinol 7 hari (ALU14). Asam urat eksogen diberikan dengan dosis 125 mg/kgBB (intraperitoneal). Allopurinol diberikan dengan dosis 50 mg/kgBB (sondase). Setelah perlakuan, mencit diterminasi pada hari ke-7, 14, dan 21, dilanjutkan pengambilan darah untuk mengukur kadar asam urat, pengambilan sampel jaringan untuk ekstraksi RNA dan pengecatan. Ekspresi mRNA TLR4 dan MCP-1 diukur menggunakan RT-PCR dan dilakukan pengecatan IHC anti-CD68 untuk visualisasi inflamasi jaringan. Hasil: Ekspresi TLR4 pada AU14 lebih tinggi dibandingkan kontrol (p<0,05), sedangkan, ekspresi TLR4 pada AU7 lebih tinggi dibandingkan kontrol, namun tidak signifikan (p>0,05). Ekspresi MCP-1 pada AU7 dan AU14 lebih tinggi dibandingkan kontrol (p<0,05). Ekspresi TLR4 pada ALU14 lebih rendah secara signifikan dibandingkan AU14 (p<0,05), sedangkan, pada ALU14 lebih rendah dibandingkan AU7, namun tidak signifikan (p<0,05). Ekspresi TLR4 pada ALU7 lebih rendah dibandingkan AU7 dan AU14, meskipun tidak signifikan (p>0,05). Ekspresi MCP-1 pada ALU14 dan ALU7 lebih rendah dibandingkan AU7 dan AU14, meskipun tidak signifikan (p>0,05). Kesimpulan: Allopurinol mampu memberikan ekspresi mRNA TLR4 yang lebih rendah, namun tidak dapat memberikan perbedaan ekspresi mRNA MCP-1 yang bermakna pada inflamasi jantung yang diinduksi asam urat.

Background: Increased uric acid level are associated with the incidence of cardiovascular disease. Uric acid is able to stimulate inflammatory response in other organs (kidney and joint) through TLR4 activation, that stimulate pro-inflammatory cytokine release, one of which is MCP-1. However, the effect of uric acid on TLR4 and MCP-1 in the heart is still unknown. Allopurinol can reduce uric acid levels, however, its effect on heart inflammation is not yet clearly known. Purpose: The aim of this study is to examine the effect of allopurinol in attenuating the inflammation of the heart, which can be seen in expression of MCP-1 (Monocyte Chemoattractant Protein 1) mRNA and TLR4 (Toll-Like Receptor 4) mRNA in mice with induced-hyperuricemia. Method: Twenty-five Swiss-Webster strain mice (3 month years old, 30-40 grams) divided into 5 groups: control, administration of uric acid for 7 days (AU7), administration of uric acid for 14 days (AU14), AU7 + allopurinol 7 days (ALU7), and AU14 + allopurinol 7 days (ALU14). Exogenous uric acid was given intraperitoneally at a dose of 125 mg/kgBW. Allopurinol was given orally at a dose of 50 mg/kgBW. After treatment, mice would be terminated on the 7th, 14th, and 21st, followed by blood collection to measure uric acid levels, tissue sampling for RNA extraction and staining. TLR4 and MCP-1 mRNA expression were measured using RT-PCR and anti-CD68 IHC staining was performed to visualize tissue inflammation. Result: TLR4 expression at AU14 was higher than control (p<0.05), whereas, TLR4 expression at AU7 was higher than control, but not significantly (p>0.05). MCP-1 expression at AU7 and AU14 was higher than controls (p<0.05). TLR4 expression at ALU14 was significantly lower compared to AU14 (p<0.05), whereas, at ALU14 it was lower than AU7, but not significantly (p<0.05). TLR4 expression in ALU7 was lower than AU7 and AU14, although it was not significant (p>0.05). MCP-1 expression in ALU14 and ALU7 was lower compared to AU7 and AU14, although it was not significant (p>0.05). Conclusion: Allopurinol is able to lower TLR4 mRNA expression, but cannot provide significant difference of MCP-1 mRNA expression in inflammation of the heart induced by hyperuricemia.

Kata Kunci : asam urat, hiperurisemia, allopurinol, inflamasi jantung, MCP-1 (Monocyte Chemoattractant Protein 1), TLR4 (Toll-Like Receptor 4)