Abnormal photoperiod exposure before pregnancy affects offspring lipid metabolism in SD rats

Exposure to constant light or shift work impairs endogenous circadian rhythm, which can lead to metabolic diseases. Previous animal and human studies demonstrated that circadian rhythm disruption during pregnancy affects the long-term health of their progeny. But circadian rhythm disruption before pregnancy would have any effect on their offspring is not thoroughly studied. This study is designed to investigate the effects from maternal circadian disruption. Randomized animal study. Fifteen 6-8 week-old adult female SD rats exposed to abnormal photoperiod (18 h:16 h light/dark cycle) and control photoperiod ( 12 h:12 h light/dark cycle) for 4 months.Thereafter, rats were housed in control photoperiod, mated, gestated and reared their offspring. At the age of 20 weeks, offspring were sacrificed every 8 hours. Tissue and plasma were harvested.Data were analyzed with t-tests. Exposure to abnormal photoperiod results in prolonged and irregular estrous cycles with regnancy rate decreased (p<0.05). Their ovary weight decreased(p<0.01), less corpus lutetium and more expanded follicles in ovary H&E stain slides. The offspring from abnormal photoperiod group not only had significantly body weight gain（male +43.1%, p<0.01; female +7.8%, p<0.05) but also higher body fat rate (female +10.1%, p<0.01). The circadian genes expression pattern in the liver were not consistent with control group. Serum LDL-c and HDL-c of female offspring elevated (p<0.05). Serum cholesterol and HDL-c of male offspring decreased (p<0.05). Abnormal light-dark cycle induced maternal circadian rhythm disruption have an effect on offspring lipid metabolism disorder in rats. As shift work, artificial night lighting, jet lag are becoming increasingly prevalent. Our finding may have the implications for people to conceive and pay attention to offspring health.