The Influences Of Branched-chain Amino Acid Imbalance On The Prognosis Of Tumor-bearing Rats During 5-Fluorouracil Chemotherapy

OBJECTIVE: To investigate the influences of the enteral nutrition (EN) of branched-chain amino acid imbalance including valine-depleted and leucine-supplemented in conjunction with chemotherapy on tumor growth and nutritional status of tumor-bearing rats.METHODS: The Sprange-dawley rats were each given a catheterization of jejunostomy and an inoculation of Walker-256 carcinosarcoma cells subcutaneously. Forty-eight rats were randomized into 4 groups: Group A (amino acid balance EN + NS), Group B (amino acid balance EN + 5-Fu chemotherapy), Group C (valine-depleted EN + 5-Fu chemotherapy), and Group D (valine-depleted and leucine-supplemented EN + 5-Fu chemotherapy). After 8 days' enteral feeding, tumor weight, tumor inhibitory rate, the change of rat's weight, the main organ weight, serum prealbumin (PA) and transferrin (Tf) concentrations, tumor cell cycle, the expression of PCNA and apoptosis were investigated. In addition, rat's survival time was observed.RESULTS: The G₀/G₁ phase ratios, apoptosis index and rat's survival time increased from group A to D in turn (P<0.05 or P<0.01). Conversely, the S phase ratios, proliferating cell nuclear antigen (PCNA) index and tumor weight decreased from group A to D (P<0.05 or P<0.01), respectively. The change of rat's weight of group C was significantly increased compared with groups A and B (P<0.05 or P<0.01). Relative weight of kidney (right and left) and muscle (left), serum PA and Tf concentrations of group C were significantly reduced compared with groups A and B (P<0.05 or P<0.01). The change of rat's weight of group D was significantly reduced compared with group C (P<0.01), relative weight of kidney (right and left) and muscle (left), serum PA and Tf concentrations of group D were significantly increased compared with group C (P<0.05 or P<0.01). The change of rat's weight, relative weight of kidney (right and left) and muscle (left), serum PA and Tf concentrations of group D have no difference with groups A and B (P>0.05).CONCLUSIONS: Valine-depleted EN and 5-Fu can effectively inhibit tumor growth, but they led to disadvantages to the nutritional status of tumor-bearing rats in the same time. Valine-depleted and leucine-supplemented EN can inhibit tumor growth and enhance the anti-tumor effect of 5-Fu chemotherapy without negative effect. Valine-depleted and leucine-supplemented EN and 5-Fu can effectively prolong the survival time of rats.