OBJECTIVE To study the efficacy and mechanism of Shugan Jianpi Jiedu decoction in the treatment of the precancerous lesions of breast cancer through animal experiment.

METHODS  SD rats were taken and divided into 6 groups(10 rats in each group), namely blank group, breast precancerous lesion model group, tamoxifen group, Shugan Jianpi Jiedu decoction groups with low dose, middle dose, and high dose. DMBA modeling method was used to carry out modeling for breast precancerous lesion. HE staining was used to observe the pathological changes of breast tissue. CD4⁺, CD8⁺ were detected by flow cytometry. ELISA was used to detect IL-2, IL-4, IL-6, IL-10, IL-12, E2, P. The protein expression of ER, PI3K, p-Akt and mTOR was detected by Western blotting.

RESULTS HE staining showed changes in rat mammary tissue, indicating successful modeling. Compared with the blank group, the content of CD4⁺ decreased and the content of CD8⁺ increased in the model group(P<0.01); compared with model group, the content of CD4⁺ increased and the content of CD8⁺ decreased in low, middle, high dose groups of Shugan Jianpi Jiedu decoction and tamoxifen group(P<0.01). The levels of IL-2, IL-4 and IL-10 in the model group were significantly lower than those in the blank group(P<0.01), while IL-12 and IL-6 were significantly increased(P<0.01). Compared with the model group, the concentrations of IL-2, IL-4 and IL-10 in the low, middle and high dose groups of Shugan Jianpi Jiedu decoction and the tamoxifen group were significantly increased(P<0.01), while IL-12 and IL-6 decreased significantly(P<0.05 or P<0.01). Compared with the blank group, the contents of E2 and P in the model group increased significantly(P<0.05 or P<0.01), the contents of E2 and P in the low, middle and high dose groups of Shugan Jianpi Jiedu decoction and the tamoxifen group were significantly lower than those in the model group(P<0.01). The Western blotting results showed that compared with the blank group, the expression of ER, PI3K, p-Akt and mTOR in the model group was significantly increased(P<0.01). Compared with the model group, the expression of ER, PI3K, p-Akt and mTOR in the low, medium and high dose groups of Shugan Jianpi Jiedu decoction and the tamoxifen group were significantly decreased(P<0.01).

CONCLUSION  Shugan Jianpi Jiedu decoction may inhibit the expression of ER, thus inhibiting the expression of PI3K/Akt/mTOR signaling pathway. Meanwhile, it can affect the immune response and reverse the precancerous lesions of breast cancer.