OBJECTIVE To study the improvement effects and its mechanism of catalpol on testicular lesions in KK-Ay spontaneous diabetic mice on the basis of glycolysis process mediated by advanced glycation end products （AGEs） and their receptors （RAGE）. METHODS KK-Ay spontaneous diabetic mice fed with high-fat diet were used as diabetic model， and then randomly divided into model group， catalpol group （100 mg/kg）， aminoguanidine group （AGEs inhibitor， 100 mg/kg） and FPS- ZM1 group （RAGE inhibitor， 1 mg/kg）， and C57BL/6J mice fed in the same period were set as normal group， with 6 mice in each group. The catalpol group and aminoguanidine group mice were given relevant medicine intragastrically， normal group and model group mice were given constant volume of normal saline intragastrically， and FPS-ZM1 group mice were given relevant medicine 1 mL/g intraperitoneally， for consecutive 8 weeks. After the last administration， the body mass， fasting blood glucose， 24-hour food intake， water consumption， urine volume， testicular organ coefficient， and sperm motility of the mice were measured； pathological morphology and ultrastructural structure of testicular tissue were observed； the levels of reduced glutathione （GSH）， superoxide dismutase （SOD）， lactate dehydrogenase （LDH） and sugar metabolites in testicular tissue of mice were detected； pathway enrichment analysis was performed； the level of AGEs in serum and testicular tissue， protein expressions of RAGE， B-cell lymphoma-2 （Bcl-2） and Bcl-2-associated X protein （Bax）， and mRNA expressions of key rate-limiting enzymes [hexokinase （HK）， phosphofructose kinase （PFK）， pyruvate kinase （PK）， LDH] in testicular tissue were alldetected. RESULT S Catalpol could significantly improve the general symptoms， testicular organ coefficients and motility ofsperm in KK-Ay spontaneous diabetic mice （P＜0.05 or P＜0.01）. The morphology and ultrastructure of spermatogenic cells in each layer of the seminiferous tubules were all improved. The levels of GSH， SOD and LDH in testicular tissue，the levels of the metabolic product glucose fructose-1，6-diphosphate， 3-phosphate glycerate， 3-phosphate glyceraldehyde， lactic acid and pyruvate， the expressions of HK， PFK， PK and LDH mRNA were all significantly increased（P＜0.05 or P＜0.01）； the levels of AGEs in serum and testicular tissue， the expression of RAGE protein and the ratio of Bax to Bcl-2 in testicular tissue were significantly decreased（P＜0.05 or P＜0.01）. Aminoguanidine and FPS-ZM1 could significantly improve the levels of most of above indicators in mice（P＜0.05 or P＜0.01）. CONCLUSIONS Catalpol shows significant improvement effects on testicular lesions of KK-Ay spontaneous diabetic mice， and its mechanism of action was associated with upregulation of AGEs/RAGE signaling pathway- mediated glycolysis.

OBJECTIVE To investigate the protective effect and potential mechanism of cornuside on diabetic nephropathy （DN） model mice. METHODS Male KK-Ay mice were fed with high-fat and high-sugar diet for two weeks to reproduce the DN model. The successfully modeled mice were randomly grouped into model group， aminoguanidine group （positive control，100 mg/kg） and cornuside group （100 mg/kg）， and male C57BL/6J mice were included as normal group， with 6 mice in each group. Administration groups were given relevant medicine intragastrically， and normal group and model group were given a constant volume of normal saline intragastrically， once a day， for 8 consecutive weeks. The levels of fasting blood glucose （FBG）， 24 h urinary protein， serum interleukin-12 （IL-12）， IL-10， blood urea nitrogen （BUN） and serum creatinine （Scr） were detected； the pathological injury， fibrotic change and glomerular microstructure of renal tissue were observed； the expressions of the receptor of advanced glycation end products （RAGE）， collagen type Ⅳ （COL-Ⅳ） and inducible nitric oxide synthase （iNOS） in renal cortex were detected in each group. RESULTS Compared with normal group， the renal cortex of mice in model group showed obvious inflammatory cell infiltration and fibrotic changes； the mesangial hyperplasia of glomerulus was serious and the basement membrane had a large number of irregular dark dense deposits； the levels of FBG and 24 h urinary protein， the serum levels of IL- 12， BUN and Scr， and the expression levels of RAGE， COL-Ⅳ and iNOS in the renal cortex were significantly increased， while the serum level of IL-10 was significantly decreased （P＜0.01）. Compared with the model group， the renal pathological injuries， fibrotic changes and glomerular microstructure of mice in administration groups were improved significantly， and the above quantitative indexes were generally improved （P＜0.05 or P＜0.01）. CONCLUSIONS Cornuside has a certain protective effect on DN model mice. It can inhibit the inflammatory response， reduce urinary protein excretion， and alleviate renal fibrosis， which may be related to the inhibition of the advanced glycation end products/RAGE signaling pathway.