The Effects of Prolonged Darkness Phase of Photoperiodic Cycle on Serum Levels of Creatine Kinase and Alkaline Phosphatase in Female Rats

Abstract

There is association between changes in photoperiodic cycle and serum level of certain enzymes. This study aims to determine the effects of prolonged darkness phase on serum levels of creatine kinase and alkaline phosphatase in female rats. In the present experimental study, female Wistar rats were randomly divided into control animals and rats experiencing prolonged darkness phase. Control animals were under normal photoperiodic cycle (12h light/ 12 h darkness), however, in the group experiencing prolonged darkness phase the animals were under 7h light and 17h darkness. After 7 weeks, blood samples were collected and serum alkaline phosphatase and creatine kinase levels were measured using spectrophotometry. The data were compared statistically between groups using ANOVA. The serum creatine kinase and alkaline phosphatase levels significantly increased in animals experiencing prolonged darkness phase compared to control rats (p<0.001and p<0.05, respectively). Our findings indicated that prolonged darkness phase leads to increased serum levels of creatine kinase and alkaline phosphatase; according to which, can impose serious pathophysiological effects on internal organs including heart, brain, liver or muscles.