Effect of lipases on hyperlipidemic acute necrotizing pancreatitis / 中华胰腺病杂志

ABSTRACT

Objective To investigate the influence of Lipoprotein lipase (LPL)/Hepatic lipase (HL) on hyperlipidemie acute necrotizing pancreatitis (HLANP) in rats. Methods The rats were fed with hyperlipidemic feed for 4 weeks, then the rats were injected with 5% sodium taurocholate into pancreatic duct to induce HLANP model. Seventy-two rats were randomly assigned to HLANP and control groups, and then each group was subdivided into 6 subgroups (n = 6) at 0, 3, 6, 12, 24 and 48 h. Serum amylase, cholesterol, triglyeride (TG), free fatty acid (FFA) levels and serum LPL, HI. activities were determined. Under the light-microscopy and electron microscopy, the histopathologic and uhrastructure changes of pancreas were observed; the HL mRNA expressions were detected by RT-PCR; HL protein expressions HL were assessed by immunohistoehemical staining. Results The serum amylase levels reached peak values at 12 h after ANP induction in the two groups, the mean values were 7 176U/L and 6 366U/L, which were significantly higher than those of baseline values (P <0.05) ; serum levels of cholesterol in HLANP group at 0 ～ 12 h were higher than those of control group, however, only at 0 h the difference (1.19±0.49 vs 0. 32±0.14 mmol/L) was significant (P < 0.05) ; serum levels of FFA in HLANP group were not significantly different when compared with those of control group; serum levels of LPL and HL at 3 h were (17.5±7) U/L and (18.6±3.9) U/L, which were significantly higher than those of control group (8.9±3.4 U/L and 9.5±2. 1 U/L, P < 0.05). The pancreatic tissues necrosis levels were significantly increased in HLANP groups (3, 6, 24 and 48 h) than those of control group at corresponding time points (P < 0.05). lipid droplet deposition, rough endoplasmic reticulum distension, zymogen granule reduction, and chondriosome swelling in acinar cells of pancreatic tissues in HLANP group were found. The HI, mRNA expressions at 3 h and 6 h in HLANP group were 1.1±0.09 and 0.89±0.08, which were significantly higher than those in control group (0. 11 ± 0.01 and 0.15±0. 03, P <0.05). HL proteins were positively expressed in pancreatic tissues of two groups before ANP was induced, and HL proteins were strongly positively expressed after ANP induction. Conclusions Lipase (LPL/HL) expression increased in HLANP rats, and the content of serum protein increased, which resulted in lipids decomposition and increased the severity of ANP. LPL/HL may be one of the key lipids metabolic enzymes aggravating HLANP.