Role of apoptosis in hepatic injury of rat and patients with Clonorchis sinensis infection

Objective To investigate the liver injury and pathological changes of rat and patients with Clonorchis sinensis(C, sinensis) infection, and to clarify the role of apoptosis in the injury induced by C. sinensis.Methods Wistar rats were divided into two group: 60 in infection group and 20 in control. The rats in infection group were infected with C. sinensis via oral feeding encysted cercaria;rats in control group were fed with normal saline. The rats were sacrificed 4, 6, 8 and 12 weeks after infection, respectively. Liver tissue specimens of the patients infected with C. sinensis were collected. The pathological changes of liver tissue were observed by light microscopy and the apoptofic rate of hepatocyte was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) assay. Results Parasites and eggs could he seen around the bile duct, and the duct was associated with mucosa and adenoma papillary hyperplasia, wall thickening, inflammatory cell infiltration, a small amount of fibrous tissue hyperplasia, and periportal liver cells surrounded by a number of nuclear condensation, all these changes meant morphological characteristics of apoptosis. Apoptotic rates of liver cells in infection group 4, 6,8 and 12 weeks after infection were (7.15 ± 1.50)%,(11.61 ± 3.09)%,(13.21 ± 3.47)% and (11.26 ± 4.06)%,respectively, which was significantly higher than that in control group [(2.57 ± 0.72)%, (3.17 + 0.77)%, (3.67 ±0.96)% and (2.84 ± 0.87)%, t values were 4.45, 5.49, 5.95 and 4.74, respectively, all P < 0.01]. Conclusions These findings indicate that C, sinensis can stimulate both hepatoeytic apoptosis and degeneration which may he related to clinical manifestations and liver lesions in patients with clonorchiasis. Key words: Clonorchis sinensis; Infection; Apoptosis; Hepatoeyte