Splenectomy reduces fibrosis and preneoplastic lesions with increased triglycerides and essential fatty acids in rat liver cirrhosis induced by a choline‐deficient L‐amino acid‐defined diet

Aim: This study investigated whether splenectomy is of significance in non‐alcoholic steatohepatitis (NASH). Methods: Five‐week‐old Wistar rats were fed a choline‐deficient diet for 8 weeks to create a NASH model. A sham‐operation or splenectomy was then performed, and rats were killed 4 weeks later. Results: Liver fibrosis and liver preneoplastic lesions were significantly reduced in the splenectomy group compared to the sham‐operation group, and α‐smooth muscle actin (SMA) expression was significantly inhibited (liver fibrosis area: sham 8.63 ± 4.09%, splenectomy 5.45 ± 3.69%, P < 0.01; preneoplastic lesion size: sham 6.56 ± 3.68 ×10⁶ µm²/cm², splenectomy 4.63 ± 3.27 ×10⁶ µm²/cm², P < 0.05; the number of preneoplastic lesions: sham 8.33 ± 3.96/cm², splenectomy 5.17 ± 1.80/cm², P < 0.01; α‐smooth muscle actin‐positive area: sham 4.41 ± 2.48%, splenectomy 2.75 ± 1.66%, P < 0.01) On the other hand, liver triglycerides and essential fatty acids were significantly increased in the splenectomy group (liver triglycerides: sham 182 ± 35.0 mg/g, splenectomy 230 ± 35.0 mg/g, P < 0.05; liver linoleic acid: sham 17.2 ± 4.9 mg/g, splenectomy 23.3 ± 6.9 mg/g, P < 0.05; liver α‐linolenic acid: sham 118 ± 36.6 µg/g, splenectomy 162 ± 51.4 µg/g, P < 0.05). In addition, expressions of hepatic fatty acid metabolism‐related genes (e.g. acyl‐CoA oxidase, liver carnitine palmitoyl‐CoA transferase I, cytochrome P450 4A, long‐chain acyl‐CoA dehydrogenase and medium‐chain acyl‐CoA dehydrogenase) were significantly inhibited in the splenectomy group. Conclusion: These findings suggest that spleen plays an important regulatory role in the fibrosis, preneoplastic lesion and lipid metabolism of liver in a rat choline‐deficient L‐amino acid model.