Journal of Dalian Ocean University  2023, Vol. 38 Issue (6): 964-971 DOI: 10.16535/j.cnki.dlhyxb.2023-061 |
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| Effects of hdac8 knockout on low temperature tolerance in zebrafish (Danio rerio) |
| SHI Xueling，LUO Juntao，LUO Beibei，HAN Bingshe，ZHANG Junfang*
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| 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 |
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Abstract To explore the effects of knocking out histone deacetylase 8 gene (hdac8) on low-temperature tolerance of zebrafish (Danio rerio), 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.
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Published: 18 January 2024
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