Pengaruh Fotoperiode Terhadap Tingkat Stres serta Ekspresi Gen Aa-NAT dan Hiomt Pada Tikus Jantan (Rattus norvegicus) Yang Dipaparkan LED Biru

• Main Author: Sarahwati P, Daur
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43060
• Institution: Institut Teknologi Bandung

Photoperiod is the periodic proportion of daytime light and nighttime darkness. Indonesia has even photoperiod owing to its geography on the equator. Nighttime human activities currently is increasing, resulting in the use of artificial light sources such as light-emitting diodes (LED) devices of various visible spectrum, including blue. Prolonged blue LED light exposure affects photoperiod and circadian rhythm which alters physiology and causes stress, depression, and mass gain from the decline of melatonine and increase of cortisol. Melatonin is a neurohormone managed by circadian rhythm. Two genes, aralkylamine N-acetytransferase (Aa-NAT) and hydroxyndole-O-methyltransferase (Hiomt) encode key enzymes of melatonine synthesis. The research is conducted to determine stress level through forced swimming test (FST) with parameters consisted of immobility duration and relative expressions of Aa-NAT and Hiomt on male rats exposed to blue LED with photoperiod variations encompassing 12L:12D, 8L:16D, and 16L:8D hours exposure to light and darkness, respectively, as well as 24L hours exposure to light using quantitative RT-PCR (qPCR). Measurement of stress level on rats was conducted through FST followed with weighing prior and after treatments. FST analysis, body mass (BB), and relative gene expression were tested statistically with ANOVA. Measurement of gene expression was performed after isolation of RNA from the brain specifically on the pineal gland region with cDNA synthesis which is used as a template for qPCR. Relative gene expression measurement was compared with house keeping gene (actine). Statistical analysis on BB showed changes although they were insignificant between treatments (P>0.05). Overall FST results showed significant differences on immobility duration between treatments (P<0.05) with highest increase recorded on 16L:8D followed with 24D. Aa-NAT expression measurement showed significant differences between treatments (P<0.05) and Hiomt expression measuremet similarly showed signidicant differences as well (P<0.05). Expression of Aa-NAT and Hiomt was the least on 24L. Based on the research, it can be condcluded that blue LED photoperiod on 16L:8D and 24L affects stress level with the parameter of immobility and blue LED photoperiod on 24L, 8L:16D, and 16L:8D decreases relative expressions of Aa-NAT and Hiomt