4.5 Anti-Angiogenesis Effects of Pei's Soft Liver and Anti-Flatulence Pill

4.5 Anti-Angiogenesis Effects of Pei's Soft Liver and Anti-Flatulence Pill

Angiogenesis is a prerequisite and essential foundation for tumor growth, invasion, and metastasis, referring to the process by which capillaries continue to form from existing vascular networks into the surrounding tissues. Hanahan et al. [66] first proposed the "angiogenic switch balance hypothesis" in 1996, suggesting that angiogenesis is jointly regulated by pro-angiogenic factors and anti-angiogenic factors. Among these, more than 30 factors are associated with tumor angiogenesis; among them, vascular endothelial growth factor (VEGF), as a vascular permeability factor, plays an especially important role in tumor angiogenesis and is currently the most extensively studied, most potent, and most specific cytokine promoting endothelial cell growth. VEGF is a heparin-binding glycoprotein that is stable under heat and acidic conditions, composed of two 23 kD subunits linked by disulfide bonds, with a relative molecular mass of 30,000–45,000, consisting of two polypeptide chains sharing the same N-terminus but differing in other regions. The human VEGF gene is located on chromosome 6p21.3, with a total length of 14 kb, comprising 8 exons and 7 introns. It primarily acts through autocrine or paracrine mechanisms to bind to corresponding receptors on endothelial cells, not only directly stimulating endothelial cell differentiation and proliferation, thereby promoting new blood vessel formation in tumors and providing ample nutrients for rapid tumor growth, but also increasing capillary permeability, forming a fibrous network and matrix that supports vascular growth and creates favorable conditions for tumor invasion and metastasis. Therefore, the level of VEGF expression reflects the degree of endothelial cell proliferation, migration, and vascular construction in tumors, directly indicating the speed of tumor growth and the tendency toward metastasis. Consequently, inhibiting VEGF expression at the genetic level and blocking VEGF-induced endothelial cell signal transduction can suppress tumor angiogenesis. There have been numerous reports on VEGF expression in hepatocellular carcinoma tissues, but most studies rely on qualitative analysis based on the number of positive cells, neglecting the intensity of staining and being easily influenced by human factors, thus failing to fully reflect changes in VEGF levels. In contrast, the use of computer image analysis systems can overcome these shortcomings, enabling quantitative or semi-quantitative analysis of VEGF and providing a more precise understanding of its expression in hepatocellular carcinoma tissues. Specifically, under the same lighting conditions, the numerical value of light absorbed or transmitted by different tissue cellular components, products of cytochemical reactions, or dye-stained results is called optical density; integral optical density (IOD) refers to the integral value of optical density within the area of the substance being measured, representing the total content of the absorbing substance. Area (A) is a commonly used parameter in morphological quantitative analysis. The area of a section equals the count of pixels falling within the section multiplied by the test area represented by each pixel. Average optical density (MOD) = IOD/A can more objectively and accurately express the amount of the measured substance. That is, the higher the MOD value, the greater the amount of the substance being measured or the deeper the color after staining, indicating a larger quantity.

This experiment found that the model group had more brown-yellow granules in the cytoplasm and the highest average optical density of staining, while VEGF expression was significantly reduced in all treatment groups, with statistically significant differences compared with the model group (p<0.05), suggesting that Ruan Gan Xiao Pi Wan can inhibit VEGF expression in H22 hepatocellular carcinoma xenografts in mice, and the reduction in VEGF expression may be one of the mechanisms by which Ruan Gan Xiao Pi Wan suppresses angiogenesis in these tumors.