Pengaruh Substitusi Tepung Kacang Gude (Cajanus cajan L.) terhadap Ekspresi Gen Carnitine Palmitoyltransferase-1B (CPT-1B) dan Kadar Enzim Citrate Synthase Otot Skelet Tikus Jantan (Rattus norvegicus galur Sprague Dawley) dengan Diet Tinggi Lemak dan Fruktosa

INDAH NUR'AINI, Prof. Dr. Dra. Sunarti, M.Kes.; dr. Arta Farmawati, Ph.D.

2021 | Tesis | MAGISTER ILMU BIOMEDIK

Latar Belakang: Diet tinggi lemak dan fruktosa dapat menyebabkan gangguan pensinyalan insulin. Pemberian diet tinggi lemak dan fruktosa dapat meningkatkan beta-oksidasi yang diawali dengan meningkatnya gen CPT-1B dan kadar citrate synthase. Akan tetapi beta-oksidasi memiliki kapasitas optimal sehingga apabila terjadi overload menyebabkan pembentukan senyawa intermediet yang dapat mengganggu pensinyalan insulin. Di dalam biji kacang gude mengandung serat. Serat pangan diketahui dapat membantu meningkatkan sensitivitas insulin. Tujuan: Penelitian ini bertujuan untuk menganalisa pengaruh substitusi tepung kacang gude (Cajanus cajan L.) terhadap ekspresi gen carnitine palmitoyltransferase-1B (CPT-1B) dan kadar citrate synthase pada tikus dengan diet tinggi lemak dan fruktosa. Metode: Subjek pada penelitian ini adalah 25 ekor tikus galur Sprague Dawley berusia 1 bulan dengan berat badan sekitar 100 g, dibagi menjadi 5 kelompok yaitu kelompok normal (N), kelompok kontrol diet tinggi lemak dan fruktosa (HF), kelompok intervensi kacang gude dosis 1 sebesar 33 g/kg pakan (HFD1), kelompok intervensi kacang gude dosis 2 sebesar 66 g/kg pakan (HFD2), kelompok intervensi kacang gude dosis 3 sebesar 99 g/kg pakan (HFD3). Induksi diet tinggi lemak dan fruktosa dilakukan selama 10 minggu sedangkan intervensi substitusi tepung kacang gude dilakukan selama 6 minggu. Ekspresi CPT-1B diukur menggunakan RT-PCR sedangkan kadar citrate synthase diukur menggunakan ELISA. Sampel yang digunakan untuk mengukur ekspresi gen CPT-1B dan kadar citrate synthase adalah otot skelet (quadriceps femoris). Hasil: Peningkatan secara signifikan (p<0,05) ekspresi gen CPT-1B dan kadar citrate synthase terjadi pada kelompok tikus yang diberikan diet tinggi lemak dan fruktosa. Setelah dilakukan intervensi, ekspresi gen CPT-1B dan kadar citrate synthase mengalami penurunan. Kelompok HFD-1 mengalami penurunan paling besar dan mendekati kelompok normal. Konsumsi substitusi kacang gude berkorelasi erat dan berbanding lurus dengan ekspresi gen CPT-1B dan kadar citrate synthase. Kesimpulan: Substitusi tepung kacang gude mampu menurunkan ekspresi gen CPT-1B dan kadar citrate synthase pada tikus model diet tinggi lemak dan fruktosa.

Background: High fat and fructose diet can lead impaired insulin signaling. Impaired insulin signaling was initiated by beta-oxidation overload. Beta-oxidation overload was characterized by increase of CPT-1B expression and citrate synthase protein level. One of nutrition that can improve insulin sensitivity was dietary fiber. Dietary fiber contains in many legumes include gude bean seed (Cajanus cajan L). Objectives: This study aim to analyzed the effect of gude bean flour substitution (Cajanus cajan L.) on the CPT-1B gene expression and citrate synthase protein level in rats with high-fat and fructose diet. Methods: The subjects of this study were 25 Sprague Dawley rats aged 1 month with body weight about 100 g, divided into 5 groups, namely the normal group (N), the control group with high fat and fructose diet (HF), the intervention group of gude bean dose 1 was 33 g/kg rat food (HFD1), intervention group of gude bean dose 2 was 66 g/kg rats food (HFD2), intervention group of gude bean dose 3 was 99 g/kg rats food (HFD3). The induction of high-fat and fructose diet was carried out for 10 weeks, while the gude flour substitution intervention was 6 weeks. Carnitine palmitoyltransferase-1B expression was measured using RT-PCR while citrate synthase protein levels were measured using ELISA. The samples of CPT-1B expression and citrate synthase level were skeletal muscle (quadriceps femoris). Result: Carnitine palmitoyltransferase-1B expression and citrate synthase protein level in HF group was significantly increased (p<0.05). After intervention, CPT-1B gene expression and citrate synthase protein levels were decreased. The HFD1 group had the greatest decrease and the value approached the normal group. The total consumption of gude bean substitution was correlated with CPT-1B gene expression and citrate synthase protein levels. Conclusion: Gude flour substitution was able to reduce CPT-1B gene expression and citrate synthase protein levels in rat with high-fat and fructose diet.

Kata Kunci : lemak, fruktosa, carnitine palmitoyltransferase-1B, citrate synthase, gude, serat/ fat, fructose, carnitine palmitoyltransferase-1B, citrate synthase, gude, fiber