Investigation into the functioning targets and mechanisms of Salvia miltiorrhiza in diabetic kidney disease treatment using network pharmacology and a rat model

Objective To predict the functioning targets of Salvia miltiorrhiza (SM) and diabetic kidney disease (DKD) by network pharmacology and validate using a DKD rat model. Methods Active ingredients present in SM were screened out using the TCMSP database. The functioning targets of each active ingredient and DKD were collected and their intersections were considered the potential functional targets of SM for DKD treatment. The potential functional targets were imported into DAVID database for GO enrichment analysis and KEGG enrichment analysis. Furthermore, a DKD rat model was constructed through intraperitoneal injection of streptozocin (STZ). The DKD rats were divided into three groups: a model group (n=9), a SM treatment group (n=9) and a valsartan treatment group (n=8). Meanwhile, another ten healthy rats were selected as a control group. Rats in each group were subjected to corresponding treatment for eight weeks. Then, the animals were scarified and their serum, 24 h urine and kidney tissues were collected. The levels of fasting blood glucose (FBG), blood urea nitrogen (BUN), serum creatinine (Scr), and 24-h urinary protein were determined. Kidney tissues were embedded and sliced, before hematoxylin-eosin staining and PAS staining. The expression of P-PI3K, P-AKT, PI3K and AKT in kidney tissues was determined by Western blot. Results According to network-based pharmacological analysis, there were 65 active ingredients in SM. These active ingredients had 170 putative gene targets, while 1,389 putative gene targets were screened for DKD. There were 83 intersections among the putative targets for DKD treatment using SM. KEGG pathway enrichment analysis suggested the potentially important role of the PI3K-AKT signaling pathway. According to animal experiment results, compared with the model group, the SM treatment group showed remarkable decreases in BUN, 24-h urinary protein and Scr levels (P<0.01). Furthermore, obvious damage was seen in DKD rats, with large amounts of accumulated collagen, which were relieved after injection with SM. Western blot results showed that, the SM treatment group presented significantly increased expression of P-PI3K and P-AKT in kidney tissues, compared with the model group (P<0.01). Conclusions Both network pharmacology and animal experiment results indicate that SM injection is effective in the treatment of DKD, which may be related to the PI3K-AKT signaling pathway.