As the population ages, the prevalence of atherosclerosis (AS), a significant cause of cardiovascular disease (CVD), continues to increase. Apoptosis is an independent risk factor for atherosclerosis. Macrophages are the primary immune cell group in AS lesions, and their apoptosis plays a crucial role in the occurrence and development of AS. There is a common mechanism of action for circular RNAs (circRNAs) that involves the sponging of microRNAs (miRNAs) by binding to the miRNA response element (MRE), thereby increasing the transcription of their target messenger RNAs (mRNAs). Most diseases are profoundly reliant on circRNAs. However, the underlying mechanism of circRNAs in apoptosis is yet to be elucidated. All differentially expressed genes (DEGs) and their expression levels were analysed by whole-transcriptome sequencing of samples from the control and nicotine groups of THP-1 macrophages. GO and KEGG analyses revealed that nicotine affects macrophage physiological processes and related pathways. GSEA focused on gene sets to better understand the potential pathways and biological functions of all mRNAs. A competitive endogenous RNA (ceRNA) regulatory network was constructed and validated through molecular biology experiments. The Notch signalling pathway was activated in nicotine-treated macrophages, and the expression of DLL4 in this pathway was increased.