Effects of hdac8 knockout on low temperature tolerance in zebrafish (Danio rerio)
SHI Xueling，LUO Juntao，LUO Beibei，HAN Bingshe，ZHANG Junfang*
1.Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources，Ministry of Education，Shanghai Ocean University，Shanghai 201306，China；2.National Demonstration Center for Experimental Fisheries Science Education，Shanghai Ocean University，Shanghai 201306，China
Abstract: To explore the effects of knocking out histone deacetylase 8 gene (hdac8) on low-temperature tolerance of zebrafish (Daniorerio), the changes in tissue damage of gill filaments, liver, and skeletal muscles, oxidative stress-related indices, and apoptosis-related gene (caspase3, caspase9, bcl-2, bax and bcl-2/bax) expression were detected in 8 months old hdac8 deficient (hdac8-/-) and wild type (WT) zebrafish exposed to low water-temperature of 8 ℃ stress from 28 ℃ to 18 ℃ at a rate of 1 ℃/h and then to 8 ℃ at a rate of 0.5 ℃/h by histological, physiological and biochemical methods and gene expression analysis. The results showed that the median lethal time (LT50) was significantly decreased under low temperature stress in hdac8-/- zebrafish, with the LT50 of 14.5 h relative to the LT50 of 21.5 h in WT zebrafish. HE staining showed that more severe damage was observed in the gill filaments, liver and skeletal muscle in hdac8-/- zebrafish compared with WT zebrafish under low temperature stress. The ATP level in hdac8-/- zebrafish showed very significant decrease (P<0.05) at 28 ℃, without significant difference in the levels of reactive oxygen species (ROS) and malondialdehyde content between WT and hdac8-/- zebrafish (P>0.05). Under low-temperature stress, however, the hdac8-/- zebrafish had very significantly higher ROS and MDA levels than the WT zebrafish did (P<0.05), and very significantly lower ATP level than the WT zebrafish (P<0.05) did. RT-qPCR revealed that there was significantly up-regulated expression level of caspase3 in hdac8-/- zebrafish (P<0.05) at 28 ℃, without significant difference in the expression levels of other antioxidant and apoptosis-related genes (P>0.05). Under low-temperature stress, the expression levels of sod, cat, caspase3, caspase9 and bax were found to be significantly up-regulated in both WT and hdac8-/- zebrafish (P<0.05), significantly higher expression levels of these genes in hdac8-/- zebrafish than those in WT zebrafish (P<0.05). In conclusion, hdac8 knockout significantly impaired the tolerance to low temperature of zebrafish, and promoted oxidative damage and cell apoptosis at low temperature.
史雪灵, 罗军涛, 罗贝贝, 韩兵社, 张俊芳. 敲除hdac8基因对斑马鱼低温耐受能力的影响[J]. 大连海洋大学学报, 2023, 38(6): 964-971.
SHI Xueling, LUO Juntao, LUO Beibei, HAN Bingshe, ZHANG Junfang. Effects of hdac8 knockout on low temperature tolerance in zebrafish (Danio rerio). Journal of Dalian Ocean University, 2023, 38(6): 964-971.
2023, Vol. 38 
