| Diabetes mellitus (DM) is a group of endocrine and metabolic diseases, which with insulin secretion or function disorder, and characterized by chronic hyperglycemia. Long-term hyperglycemia and metabolic disorders lead to macroangiopathy and microangiopathy which harmed to human health. Diabetic nephropathy(DN), one of the diabetic microvascular complications, is characterized by diffuse glomerular basement membrane thickening, glomerular mesangial expansion and renaltubulo-interstitial fibrosis. Recently, studies demonstrated that in addition to the insulin deficiency, a variety of glucagonis also involved in diabetes and its complication, such as growth hormone, glucagon, glucocorticoid. Currently, growth hormone(GH) and insulin-like growth factor-1 (IGF-1) are considered to be involved in the progress of diabetes and the development of diabetic nephropathy.Patients with type 1 diabetes or type 2 diabetes have GH/IGF-1 system disorders. And excessive GH secretion is the performance poor control of type 1 diabetes. The deficiency of insulin in T1DM lead to the decreased of GH-induced IGF-1 synthesis. While the reduce of IGF-1 level in turn to weaken the negative feedback of GH inhibition, resulting in the higher level of GH and GH resistance. Becasuse GH can increase glucose and IGF-1 which has the insulin-like effct, the high level of GH and low level of IGF-1 made the control of blood glucose much more diffcult. Moreover, the presence of GH and IGF-1 with high level in kidney tissues, act as growth factors, which have strong effect of the promotion cell proliferation. And through the activation of MAPK (mitogen activated protein kinase) system signal pathway, they can lead to the renal cell proliferation, glomerular hypertrophy, mesangial matrix accumulation, and eventually development to the glomerular sclerosis and renal tubule-interstitial fibrosis.In the traditional Chinese medical science, "diabetes" is casused by the dysfunction of "spleen"(i.e., pancreas). "Tonifying spleen and transporting essential" is the main principle of Jinlida granules. Jinlida granules consist of ginseng and astragalus, polygonatum, perrin, tuckahoe etc. Through strengthen the function of "spleen", Jinlida granules can effectively control the blood glucose and reduce the complications of diabetes. It has been confirmed that Jinlida granules can alleviate inflammation, oxidative stress and protect the islet β cells.This research is mainly to study the influence of Jinlida granules on GH/IGF-1 system and kidney in type 1 diabetes mellitus rats after 8 weeks of different doses of Jinlida granules, Jinlida+Tongxinluo compound preparation, metformin, saxagliptin treatment. The experiment was divided into two parts, the first part:observe the effect of Jinlida granules on GH/IGF-1 system in type 1 diabetic rats by detect blood glucose, glycosylated hemoglobin, C peptide, growth hormone, insulin like growth factor-1, insulin like growth factor binding protein-1 and liver growth hormone receptor level; the second part:observe whether Jinlida granules have protective effect on the kidney in type 1 diabetic rats by detect GH/IGF-1 system level and MAPK expression in kidney, and the HE staining, masson staining, PAS staining with kidney tissue.ObjectiveTo investigate the effect of the different dosage of Jinlida granules on GH/IGF-1 system and kidney in type 1 diabetes mellitus rats. Explore Jinlida granules’influence and possible mechanism in the kidney and further study the role of Jinlida granules.MethodsType 1 diabetic SD rats models were induced by intraperitoneal injection of streptozotocin (STZ 60mg/kg). The study was randomly divided into diabetic model group, low/medium/high doses of Jinlida granules group, medium Jinlida+TXL group, metformin group, saxagliptin group and normal control group. Each group was administered drug or placebo orally for 8 weeks. The first part:detect these indicators, include fasting serum glucose (FBG), glycosylated hemoglobin (HbA1C), insulin (FINS), C peptide, growth hormone (GH), insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-1 (IGFBP-1) (RIA, ELISA, etc); Hepatic growth hormone receptor (GHR) mRNA (RT-PCR). The second part:kidney GH, GHR, IGF-1, IGF-1R, IGFBP-1 mRNA are detected by realtime-PCR; kidney MAPK system and fibronectin (FN) are detected by Western blot. HE staining, masson staining, PAS staining with kidney tissue.Results1. Blood biochemical indexes:Compared with the normal control group, the diabetic model group’s FBG, HbA1C were significantly increased (P<0.01), and FINS, C peptide were significantly decreased (P<0.01). Compared with the diabetic model group, the level of FBG were significantly decreased (P<0.05, P<0.01) in the medium dose Jinlida granules group, high dose Jinlida granules group, medium Jinlida+Tongxinluo group, metformin group and saxagliptin group; the level of HbA1C were significantly decreased (P<0.05, P<0.01) in the medium dose Jinlida granules group, high dose Jinlida granules group, medium Jinlida+Tongxinluo group and metformin group; the level of FINS were significantly incresased(P<0.05, P<0.01) in all Jinlida granules group, medium Jinlida+ Tongxinluo group and metformin group; the level of C peptide were significantly increased (P<0.05, P<0.01) in each drug treatment groups.2. The GH/IGF-1 system indexes in circulation:Compared with the normal control group, the diabetic model group’s GH, IGFBP-1 were significantly increased (P<0.01), the levels of IGF-1 were significantly decreased (P<0.01), the levels of GHR mRNA were significantly decreased in liver (P<0.05). ComPared with the model group, the levels of GH were significantly decreased (P<0.01) and the levels of IGF-1were significantly increased (P<0.01) in each drug treatment group; the levels of IGFBP-1were significantly decreased (P<0.05, P<0.01) in the low dose Jinlida granules group, high dose Jinlida granules group and medium Jinlida+Tongxinluo group; the levels of liver GHR mRNA were significantly increased (P<0.05, P<0.01) in the medium Jinlida+Tongxinluo group and metformin group.3. THE GH/IGF-1 system indexes in kidney tissue:Compared with the normal control group, the mRNA levels of renal GH, GHR, IGF-1, IGF-1R, IGFBP-1 were significantly increased (P<0.01) in diabetic model group. Compared with the model group, the mRNA levels of renal GH were significantly decreased (P<0.01) and the mRNA levels of renal IGF-1 were significantly increased (P<0.01) in the medium dose Jinlida granules group, high dose Jinlida granules group, medium Jinlida+Tongxinluo group and metformin group; the mRNA levels of renal GHR were significantly decreased (P<0.01) in each drug treatment groups; the mRNA levels of renal IGF-1R were significantly decreased (P<0.05, P<0.01) in each drug treatment groups except saxagliptin group; the mRNA levels of renal IGFBP-1 were significantly decreased(P<0.05) in the medium Jinlida+Tongxinluo group.4. The MAPK system and FN in kidney tissue:Compared with the normal control group, the levels of renal p-ERK/ERK, p-JNK/JNK, FN were significantly increased (P<0.01) and the levels of renal p-p38/p38 were significantly decreased (P<0.01) in diabetic model group. Compared with the model group, in addition to the low-dose Jinlida granules group, other groups’ p-ERK/ERK and p-JNK/JNK were significantly decreased (P<0.05, P<0.01); each drug treatment groups’ p-p38/p38 were significantly increased (P<0.01) and FN were significantly decreased (P<0.01).5. The morphology of kidney tissue:HE staining showed that the glomerular profile, the renal tubular structure and the boundaries between cells were clear in normal control group. In diabetic model group, the glomerulars’outline, tubular structure were and the boundaries between cells were vague, and the number of glomerulars were decreased. Masson staining showed, compared with the normal group, the blue staining areas of renal tubular-interstitial were increased in model group, which means colloid deposition and renal interstitial fibrosis. PAS staining showed that the purple-red areas in glomerular were increased. The glomerular mesangial areas and basemen membrane were thickening. The morphology changes in kidney were alleviated in the medium Jinlida granules group, high dose Jinlida granules, medium Jinlida+Tongxinluo group and metformin group.ConclusionJinlida granules can restore the disorders of growth hormone/insulin-like growth factor-1(GH/IGF-1) system, and has a protective effect on the kidney. |
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