Qingrexiaozheng formula (QRXZF) has been shown to be effective in improving kidney injury in diabetic kidney disease (DKD) , but the mechanism remains to be unclear.

To explore the effect and mechanism of action of QRXZF in the improvement of kidney injury induced by unilateral nephritic resection combined with streptozotocin (STZ) in DKD rats.

The experiment was implemented from July to November, 2019. Thirty healthy SPF male SD rats were randomly divided into sham operation group (NC group, n=10) and model group (n=20) . Rats in NC group received 1 cm transverse incision performed at the body surface anatomical position of the right kidney and sutured, and intraperitoneal injection of citric acid buffer when the wound healed one week later. Those in model group were treated with right nephrectomy, and received a single intraperitoneal injection of STZ solution (55 mg/kg) with the same volume as the citric acid buffer for the NC group one week later to establish the DKD model. Then rats in the model group were randomly divided into DKD subgroup (n=10) and QRXZF subgroup (n=10) when the modeling was successfully achieved. After this, rats in NC group and DKD subgroup received intragastric administration of the same amount (1 ml/100 g) of 0.9% sodium chloride solution once a day, and those in QRXZF subgroup received intragastric administration of QRXZF at a dose of 7.92 g·kg^-1·d^-1. During the intervention, weight was measured every week. After 16 weeks of intervention, a 24-hour urine, serum and kidney tissue specimens were collected, kidney weight was measured, and the kidney weight index was calculated. Enzyme-linked immunosorbent assay was used to detect the microalbumin in 24-hour urine (24 hUpro) . The automatic biochemical analyzer was used to analyze serum creatinine (Scr) , blood urea nitrogen (BUN) and serum albumin (ALB) . Hematoxylin-eosin staining, Periodic Acid-Schiff staining and Masson's trichrome staining were performed to observe the damage degree of kidney tissue. Immunohistochemical method was used to detect the expression level of Caspase-3 and p16 in kidney tissue. The apoptosis of renal tubular cells was detected by in situ terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling.

Compared with rats in the NC group, those in DKD and QRXZF subgroups had lower weight and higher kidney weight index (P<0.01) . Rats in QRXZF subgroup had higher weight and lower kidney weight index than those in DKD subgroup (P<0.01) . In comparison to rats in the NC group, rats in DKD subgroup had higher levels of 24 hUpro, Scr and BUN lower level of ALB (P<0.01) , and those in QRXZF subgroup had higher levels of 24 hUpro and BUN, and lower level of ALB (P<0.01) . Rats in QRXZF subgroup had higher levels of 24 hUpro, Scr and BUN, and lower level of ALB than did those in DKD subgroup (P<0.01) . Compared with rats in the NC group, obvious pathological injury, glomerular hypertrophy and interstitial tubular fibrosis were observed in kidney tissues in rats of both DKD and QRXZF subgroups, but the degree of pathological changes was much lighter in QRXZF subgroup. Immunohistochemistry analysis showed that the expression levels of P16 and Caspase-3 in renal tissue in DKD or QRXZF subgroup were higher than those in NC group (P<0.01) . The expression levels of P16 and Caspase-3 in renal tissue in QRXZF subgroup were lower than those in DKD subgroup (P<0.01) . The rate of renal tubular cell apoptosis in DKD or QRXZF subgroup was higher than that in NC group (P<0.01) . The rate of renal tubular cell apoptosis in QRXZF subgroup was lower than that in DKD subgroup (P<0.01) .

QRXZF effectively improved the renal function, attenuate the pathological damage and fibrosis of the kidney, inhibit the expression of Caspase-3 and p16 in renal tissues, and decrease the rate of renal tubular cell apoptosis in DKD rats, suggesting that the mechanism of QRXZF in improving kidney may be related to inhibiting the aging and apoptosis of kidney cells.

清热消癥方对糖尿病肾病（DKD）肾损伤有保护作用，然而机制尚不十分明确。

探讨清热消癥方在单侧肾切除联合链脲佐菌素（STZ）诱导的DKD大鼠肾损伤中的保护作用及机制。

2019年7—11月，将30只SPF级健康雄性SD大鼠随机分为假手术组（NC组，n=10）和模型组（n=20）。NC组大鼠于右肾体表解剖位置做1 cm的横行切口并缝合；模型组大鼠予右侧肾切除。1周后，大鼠伤口愈合后，NC组大鼠给予等量柠檬酸缓冲液腹腔注射；模型组大鼠予单次腹腔注射STZ（55 mg/kg）的方法构建DKD模型。成模后将模型组大鼠随机分为DKD亚组（n=10）和清热消癥方亚组（QRXZF亚组，n=10）。NC组和DKD亚组大鼠灌服等量（1 ml/100 g）0.9%氯化钠溶液，1次/d。QRXZF亚组大鼠以7.92 g·kg^-1·d^-1的剂量予中药灌胃。干预期间每周对大鼠称重。干预16周后留取大鼠24 h尿、血清、肾组织标本，并称取肾脏重量，计算肾重指数。采用酶联免疫吸附试验（ELISA）检测大鼠24 h尿微量白蛋白（24 hUpro）水平，全自动生化分析仪检测大鼠血肌酐（Scr）、血清尿素氮（BUN）和血清白蛋白（ALB）。将肾脏组织进行苏木素-伊红（HE）染色、糖原（PAS）染色、Masson染色，观察大鼠肾脏组织损伤程度。免疫组化法（IHC）检测各组大鼠肾组织Caspase-3和p16表达情况。原位末端脱氧核苷酸转移酶标记技术（TUNEL）法检测肾小管细胞凋亡率。

DKD亚组、QRXZF亚组体质量均低于NC组、肾重指数均高于NC组（P<0.01）；QRXZF亚组体质量高于DKD亚组、肾重指数低于DKD亚组（P<0.01）。DKD亚组24 hUpro、Scr、BUN水平均高于NC组，ALB水平低于NC组（P<0.01）；QRXZF亚组24 hUpro、BUN水平均高于NC组，ALB水平低于NC组（P<0.01）；QRXZF亚组24 hUpro、Scr、BUN水平均低于DKD亚组，ALB水平高于DKD亚组（P<0.01）。与NC组相比，DKD亚组和QRXZF亚组大鼠肾脏均出现明显病理损伤，肾小球肥大和间质小管纤维化，但QRXZF亚组病变程度较DKD亚组明显减轻。免疫组化结果表明，DKD亚组、QRXZF亚组肾组织p16、Caspase-3表达水平均高于NC组，QRXZF亚组肾组织p16、Caspase-3表达水平均低于DKD亚组（P<0.01）。DKD亚组、QRXZF亚组大鼠肾小管细胞凋亡率高于NC组，QRXZF亚组肾小管细胞凋亡率低于DKD亚组（P<0.01）。

清热消癥方可有效改善DKD大鼠的肾功能，抑制肾脏病理损伤和纤维化，抑制DKD大鼠肾组织中Caspase-3和p16的表达，降低肾小管细胞凋亡率。提示清热消癥方发挥肾保护作用的机制可能与抑制肾脏细胞衰老和凋亡有关。