Abstract: Objective:To explore the role of portal venous pressure changes in the liver dysfunction caused by hepatic congestion after extended liver resection.
Methods:The experimental study was adopted. According to the random number table, 90 SpragueDawley rats were divided into 3 groups, 30 in each group: 30 rats in the noncongestion group received 70% of liver resection (median lobe+left lobe), 30 rats in the congestion group received 70% of liver resection (median lobe+left lobe) with whole caudal lobe congestion by ligation of veins and 30 rats in the congestion+splenectomy group received 70% of liver resection (median lobe+left lobe) with whole caudal lobe congestion by ligation of veins and splenectomy. (1) Twenty rats in each group were used to make postoperative survival analysis.Ten rats in each group were used for related experiments. The portal venous pressures (PVPs) of 5 rats in each group were detected at postoperative 12 hours and 24 hours, and then blood and liver specimens were collected. (2) PVP changes were detected at postoperative 12 hours and 24 hours. (3) Clinical and biochemical test: level of total bilirubin (TBil) was tested at postoperative 12 hours and 24 hours. (4) Pathological examination: liver pathological damage was detected by HE staining. (5) The expression of CD68 macrophagocyte was detected by immunohistochemical staining. (6) The relative expressions of Cleaved Casepase-3 and hypoxia inducible factor1α (HIF-1α) proteins at postoperative 24 hours were detected by Western blot. (7) The relative expressions of mRNA of vascular regulation related genes (ET-1/eNOS) and inflammatory factors (TNFα and IL-6) were detected by realtime polymerase chain reaction (RTPCR). (8) The hyaluronic acid (HA) was measured by enzymelinked immunosorbent assay (ELISA). Measurement data with normal distribution were represented as ±s. Comparison among 3 groups was done using the ANOVA, and pairwise comparison was done by the LSD test. The postoperative 5day survival curve was drawn by the KaplanMeier method, and the survival was compared using the Logrank test.
Results:(1) Survival analysis: 5day survival rate in the noncongestion group, congestion group and congestion+splenectomy group were respectively 75%, 10% and 55%, with a statistically significant difference among the 3 groups (χ²=18.21, P<0.05). (2) Changes of PVPs and TBil: levels of PVP and TBil in the noncongestion group, congestion group and congestion+splenectomy group were respectively (15.77±0.67)cmH₂O, (18.33±0.28)cmH₂O, (14.87±0.58)cmH₂O, (1.48±0.10)μmol/L, (1.76±0.15)μmol/L, (1.62±0.11)μmol/L at postoperative 12 hours and (13.49±0.45)cmH₂O, (16.96±0.82)cmH₂O, (15.69±0.85)cmH₂O, (1.47±0.11)μmol/L, (1.94±0.07)μmol/L, (1.67±0.11)μmol/L at postoperative 24 hours, showing statistically significant differences among 3 groups (F=56.53, 29.01, 6.81, 27.85, P<0.05). (3) Results of pathological examination: compared with noncongestion group, there were a lot of vacuolar cells with degeneration appearing in noncongestion liver tissues, severe liver cell swelling and hepatic sinus congestion in the congestion group at postoperative 24 hours. Compared with congestion group, vacuolar degeneration appearing in noncongestion liver tissues have some improvement in the congestion+splenectomy group. (4) Immunohistochemical staining: compared with noncongestion group and congestion+splenectomy group, the positive CD68 marked macrophages in the congestion group were increased at postoperative 24 hours. (5) Western blot assay: the relative expressions of Cleaved Casepase-3 and HIF-1α proteins in the noncongestion group, congestion group and congestion+splenectomy group were 0.63±0.05, 1.17±0.18, 0.95±0.17 and 0.63±0.14, 1.48±0.08, 1.13±0.17, respectively, showing statistically significant differences among 3 groups (F=17.42, 50.58, P<0.05). (6) Results of RTPCR: the relative expression of mRNA of ET-1/eNOS in the noncongestion group, congestion group and congestion+splenectomy group was respectively 1.01±0.63, 2.09±0.27, 0.82±0.12 at postoperative 12 hours and 0.73±0.17, 2.16±0.94, 0.80±0.24 at postoperative 24 hours, showing statistically significant differences among 3 groups (F=62.91, 10.65, P<0.05). The relative expression of mRNA of TNFα in the noncongestion group, congestion group and congestion+splenectomy group was respectively 0.99±0.08, 127.80±13.15, 7.34±1.56 at postoperative 12 hours and 0.99±0.06, 116.62±13.32, 58.62±12.12 at postoperative 24 hours, showing statistically significant differences among 3 groups (F=436.77, 154.54, P<0.05). The relative expression of mRNA of IL-6 in the noncongestion group, congestion group and congestion+splenectomy group was respectively 0.98±0.06, 1.87±0.34, 1.54±0.15 at postoperative 12 hours and 0.99±0.05, 2.02±0.27, 1.51±0.11 at postoperative 24 hours, with statistically significant differences among 3 groups (F=22.08, 46.71, P<0.05). (7) Results of ELISA: the level of HA in the noncongestion group, congestion group and congestion+splenectomy group was respectively (149±9)ng/L, (200±19)ng/L, (174±9)ng/L at postoperative 12 hours and (136±16)ng/L, (202±13)ng/L, (91±11)ng/L at postoperative 24 hours, with statistically significant differences among 3 groups (F=19.23, 34.68, P<0.05).
Conclusions:On the basis of extended liver resection, a wide range of liver congestion through increasing PVP causes hepatic microcirculation disorders, hypoxia, inflammation, vacuoles degeneration cells, increased cells apoptosis, aggravated damage of liver function and increased mortality of rats. Splenectomy could reduce PVP and then improve the liver tissues damage caused by liver congestion, meanwhile, increase the survival rate of rats.