Study on the Anti-thymic Atrophy Effects of Different Extracts from Root Tubers of Tetrastigma Hemsleyanum Diels et. Gilg

OBJECTIVE To compare the anti-thymic atrophy effects of petroleum ether(PEE), ethyl acetate(EAE), n-butanol(BE) and water extract(WE) fractions from root tubers of Tetrastigma hemsleyanum Diels et. Gilg based on mice thymic atrophy model established by intraperitoneal injection of PolyI:C to preliminarily investigate the mechanisms of its effects.

METHODS  One hunderd ICR mice were randomly divided into 10 groups: control group, model group, low- and high-dose groups of the four extract fractions, with 10 mice in each group. The control group and model group were given equal volume of purified water and gavaged for 10 d. Starting on the 9th day, PolyI:C solution of 16 mg·kg⁻¹ was injected intraperitoneally for 2 consecutive days, except for the control group, which was injected intraperitoneally with physiological saline. Samples of thymics were weighed and and visceral index was calculated, blood samples were taken for analysis of IL-2, TNF-α and WBC, thymic histopathology was analyzed using hematoxylin-eosin staining, Western blotting was performed to detect the expression of TNF-α, p-NF-κB and NF-κB.

RESULTS Compared with the model group, all groups of extracts could enhance the thymus weight and thymus index, as well as the cortex and medulla area ratio and the number of thymic corpuscles in 1 mm² of medulla to different degrees, and at the same time, significantly reduce the level of TNF-α in plasma, evidently inhibited the phosphorylation of NF-κB, and reduced the protein expression of TNF-α, and each of them having distinct advantages and disadvantages. Peripheral blood white blood cell, lymphocyte absolute count and lymphocyte percentage were elevated in the low-dose WE group, low-dose EAE group and high dose PEE group, IL-2 levels were significantly elevated in the low-dose WE group and high dose BE group, and these effects were particularly well demonstrated.

CONCLUSION Four extracts from root tubers of Tetrastigma Hemsleyanum Diels et. Gilg can improve morphological changes and atrophy of the thymus tissue in different degrees, regulate of peripheral blood leukocyte imbalance in post-modeling mice, it may be related to the inhibition of PolyI:C-induced phosphorylation of the NF-κB and reduction of protein expression of pro-inflammatory factors.