PENGARUH TEPUNG LABU KUNING (Cucurbita moschata) TERHADAP JARINGAN ADIPOSA PUTIH DAN HEPAR TIKUS YANG DIINDUKSI DIET TINGGI LEMAK DAN FRUKTOSA Kajian Ekspresi Gen Retinol Binding Protein-4 (RBP4) dan Phosphoenolpyruvate Carboxykinase (PEPCK)

DIANANDHA SEPTIANA R, Dr. Sunarti, M.Kes; dr. Ahmad Hamim Sadewa, Ph.D

2016 | Tesis | S2 Ilmu Kedokteran Dasar dan Biomedis

Latar belakang: Diet tinggi lemak dan fruktosa (DTLF) diketahui dapat menyebabkan stres oksidatif yang berakibat pada resistensi insulin dan ditandai dengan tingginya homeostasis model assessment of insulin resistance (HOMA - IR), ekspresi restinol binding protein 4 (RBP4), serta phosphoenolpyruvate carboxykinase (PEPCK). Karotenoid yang terdapat pada labu kuning diketahui dapat mengurangi stres oksidatif. Tujuan: Mengetahui pengaruh pemberian tepung labu kuning terhadap HOMA - IR, ekspresi gen RBP4, dan PEPCK pada tikus yang diinduksi DTLF. Metode: Sebanyak 25 ekor tikus Sprague Dawley digunakan dalam penelitian ini. Tikus dibagi menjadi 5 kelompok: 1) normal; 2) DTLF; 3) DTLF + 0,16 g / 200 g BB tepung labu kuning; 4) DTLF + 0,32 g / 200 g BB tepung labu kuning; 5) DTLF + 0,64 g / 200 g BB tepung labu kuning. Tikus diinduksi DTLF selama 25 hari dan diberi tepung labu kuning selama 4 minggu. Analisis HOMA - IR, ekspresi gen RBP4 di jaringan adiposa putih, dan PEPCK di jaringan hepar dengan metode quatitative polymerase chain reaction (qPCR) dilakukan di akhir penelitian. Hasil: Nilai HOMA - IR pada kelompok yang diinduksi DTLF dan diberi tepung labu kuning lebih rendah dibandingkan dengan kelompok yang diinduksi DTLF tanpa tepung labu kuning (p = 0,007). Ekspresi RBP4 baik pada kelompok yang diinduksi DTLF dan diberi tepung labu kuning maupun diinduksi DTLF tanpa tepung labu kuning tidak berbeda (p = 0,625). Ekspresi PEPCK pada kelompok yang diinduksi DTLF dan diberi 0,16 g / 200 g BB tepung labu kuning lebih rendah (3,18 +- 0,04) dibandingkan dengan kelompok yang diinduksi DTLF tanpa tepung labu kuning (p = < 0,001). Kesimpulan: Pemberian tepung labu kuning pada tikus yang diinduksi DTLF dapat memperbaiki resistensi insulin. Tingkat eskpresi PEPCK pada kelompok yang diberi tepung labu kuning 0,16 g / 200 g BB lebih rendah, namun tingkat ekspresi RBP4 tidak mengalami perubahan.

Background: High fat and fructose diet (HFFD) induced oxidative stress and cause insulin resistance that marked by high of homeostasis model assessment of insulin resistance (HOMA - IR), high of retinol binding protein 4 (RBP4), and phosphoenolpyruvate carboxykinase (PEPCK) gene expression. Carotenoid in pumpkin may be reduce oxidative stress. Objectives: This study to evaluate the effect of pumpkin powder on HOMA - IR, RBP4 and PEPCK gene expression in rats induced HFFD. Methods: Twenty five (25) male Sprague Dawley rats were used in this study. Five healthy rats were maintained and served as a control. Twenty healthy rats were divided into 4 groups: HFFD control, HFFD with 0.16 g / 200 g body weight (BW) of pumpkin powder; HFFD with 0.32 g / 200 g BW of pumpkin powder; HFFD with 0.64 g / 200 g BW of pumpkin powder. Rats were induced HFFD during 25 days and the pumpkin powder were administrated for 4 weeks. At the end of treatment the HOMA - IR and tissues gene expression of RBP4 (from white adipose tissue) and PEPCK (from liver tissue) were meassured. Result: The HOMA - IR index was significantly lower in all treatments group (p = 0.007), with the lowest HOMA - IR index observed in 0.64 g / 200 g BW of pumpkin powder. There was no significantly difference RBP4 expression in white adipose tissue between HFFD group and all treatment groups (p = 0.625). The PEPCK gene expression in liver tissue was significantly difference between HFFD group and all treatment groups (p = < 0.001), with the lowest expression observed in 0.16 g / 200 g BW of pumpkin powder. Conlusion: Pumpkin powder can improve insulin resistance in HFFD rats and decrease PEPCK gene expression possibly by reducing oxidative stress, altough there was no change in RBP4 gene expression.

Kata Kunci : Diet tinggi lemak dan fruktosa, stres oksidatif, resistensi insulin, ekspresi gen RBP4, ekspresi gen PEPCK; High fat and fructose diet, oxidative stress, insulin resistance, RBP4 gene expression, PEPCK gene expression