Life long effects of radiation and high fat dieat on the mouse left ventricular tissue
We studied the long-term effects of single whole-body gamma and simulated GCR irradiation (IR) and consumption of a Western Diet (WD) on the heart's left ventricle (LV). Three-month-old C57Bl/6J wild-type male and female mice were assigned to the following groups: 1) Gamma-irradiated with follow-up at 440(males and females) and 660(males)/550(females) days post-IR; 2) simGCRsim-irradiated with follow-up at 440(males and females) and 660(males)/550(females) days post-IR; 3) 270-days WD-fed animals with followup at 530 (males and females) and 750(males)/640(females). Control groups consisted of non-irradiated (non-IR) mice and normal diet-fed mice. Control groups were followed up similarly to the treatment groups.  LV tissues were collected at follow-up and subjected to bulk RNA sequencing analysis.  Total RNA was extracted from LV tissues using the RNeasy Mini Kit (Qiagen, USA) according to the manufacturer's protocol and stored at -80°C until further use. A poly-A selected mRNA library was prepared using the NEBNextUltra™II RNA Library Prep Kit. The sequencing was performed on the Illumina NovaSeq-6000 platform to collect an average of 48 million 2x150bp paired-end reads per sample.FastQC (version 0.11.9) was used for the quality assessment of raw sequencing reads (Q30% was greater than 94%). Next, we aligned the reads to the mouse reference genome (mm39) with STAR aligner (version 2.7.8a) with gene count quantification mode and obtained raw gene counts. Differential gene expression analysis and functional annotation were performed using DeSeq2 and fgsea R packages.  The results of the studies provide insight into the long-term transcriptome disturbance in response to irradiation and the Western diet, their association with structural and functional changes in LV, and implications in the development of cardiovascular disease (CVD). Furthermore, the study results pointed to the strong sex-biased pathophysiological and transcriptomic changes in LV. Overall design: Total RNA was extracted from LV tissues using the RNeasy Mini Kit (Qiagen, USA) according to the manufacturer's protocol and stored at -80°C until further use. A poly-A selected mRNA library was prepared using the NEBNextUltra™II RNA Library Prep Kit. The sequencing was performed on the Illumina NovaSeq-6000 platform to collect an average of 48 million 2x150bp paired-end reads per sample.