Research Article: Screening for the protective effect target of deproteinized extract of calf blood and its mechanisms in mice with CCl4-induced acute liver injury

Date Published: July 10, 2017

Publisher: Public Library of Science

Author(s): Guangyu Xu, Xiao Han, Guangxin Yuan, Liping An, Peige Du, Gianfranco D. Alpini.


Liver injury is a common pathological basis of various liver diseases, and long-term liver injury is often an important initiation factor leading to liver fibrosis and even liver cirrhosis and hepatocellular carcinoma (HCC). It has been reported that deproteinized extract of calf blood (DECB) can inhibit the replication of hepatitis B virus and confers a protective effect on the liver after traumatic liver injury. However, few studies on the regulatory factors and mechanisms of DECB have been reported. In this current study, an acute mouse liver injury model was established with carbon tetrachloride (CCl4). The differentially expressed genes and related cell signal transduction pathways were screened using mRNA expression microarray. STEM software V1.3.6 was used for clustering gene functions, and the DAVID and KEGG databases were applied for the analysis. A total of 1355 differentially expressed genes were selected, among which nine were validated by RT-qPCR. The results showed that the Fas, IL1b, Pik3r1, Pik3r5, Traf2, Traf2, Csf2rb2, Map3k14, Pik3cd and Ppp3cc genes were involved in the regulation of DECB in an acute mouse liver injury model. Targets of the protective effects of DECB and its related mechanisms were found in mice with acute liver injury induced by carbon tetrachloride, which may provide an important theoretical basis for further DECB research.

Partial Text

Liver injury is defined as acute liver dysfunction caused by viral infection, liver toxicity, toxic substances or hepatic ischemia reperfusion, and the common pathological basis of various liver diseases is generally characterized by pathological characteristics such as liver cell degeneration, necrosis, and apoptosis [1]. Long-term liver injury can often lead to liver fibrosis and is an important initiating factor in the occurrence of liver cirrhosis and hepatocellular carcinoma (HCC) [2]. Therefore, the prevention and treatment of liver injury is a major step in the clinical treatment of liver diseases, and controlling liver injury occurrence and development hold great clinical significance for the treatment of liver diseases [3].

CCl4-induced liver injury model is a classical model that is commonly used to study the liver, liver drug efficacy and mechanisms of action [11]. The currently accepted mechanism of CCl4-induced liver injury is that CCl4 can generate CCL3 and CCl3O2 radicals through activation of hepatic microsomal cytochrome P450. These free radicals can covalently bind to macro-molecules in liver cells and attack unsaturated lipids under the cytoplasmic membrane to induce lipid peroxidation (LPO). LPO and its degradation products can also cause damage to the stability and integrity of a variety of biological membranes and increase their permeability, resulting in the outflow of enzymes in the cytoplasm into the blood, such as ALT and AST [12,13]. Therefore, the determination of ALT and AST activities in the serum is an important index for evaluating liver injury. In the current experiment, the activity of serum ALT and AST in the DECB group was significantly lower than that in the model group, suggesting that DECB may exert a protective effect on CCl4-induced acute liver injury. The metabolic end-product MDA of lipid peroxides can reflect the degree of oxidation reaction and induce cell damage in the body [14,15]. SOD is the main defensive antioxidant enzyme in cells, which can clear free radicals, mitigate the chain reaction of lipid peroxidation, and protect the structural stability and functional integrity of membranes. It is believed that MDA content and SOD activity can indirectly reflect the level of oxygen free radicals, and the GSH level can reflect the body’s antioxidant capacity [16]. The results showed that SOD activity and GSH level were significantly increased, while MDA content was significantly decreased in the DECB group, indicating that DECB can enhance the antioxidant capacity of the liver and reduce the formation of lipid peroxides. DECB extracted and purified from calf serum by ultrafiltration and concentration technologies mainly consists of small molecular substances, such as inorganic ions (potassium, sodium chloride, etc.), small peptides, amino acids, and sugars. Polypeptide concentrations and the contents of DECB products from various manufacturers differ. Higher contents of polypeptides confer stronger in vivo antioxidant ability, suggesting that the effective antioxidant components of DECB could be the polypeptides [4].

The Fas, IL1b, PIK3R1, Pik3r5, Traf2, Csf2rb2, Map3k14, Pik3cd and Ppp3cc genes were closely associated with cell apoptosis. Fas, Pik3r, Traf2, Ppp3cc and Pik3cd may be important factors of apoptosis-related signaling pathways, and IL1β could regulate and control cellular inflammatory responses and promote cell apoptosis. Although a few studies on Csf2rb2, Map3k14 and Pik3r5 have been recently published, the highly significant P value revealed by the RT-qPCR results indicates that Pik3r5 may be the key factor of apoptosis.




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