Effects of triangle grass decoction on bone metabolism in rats with chronic kidney disease complicated with mineral and bone abnormalities

Abstract

Ethnopharmacological relevance: Triangle grass is a liliaceous Chlorophytum perennial herb of ChlorophytumlaxumR.Br. It is distributed mainly in Guangdong and Guangxi Provinces of China. The initial use of triangle grass was mainly to treat bone pain and swelling caused by a fall injury. Triangle grass tablets (NO. Z20070544) are also used as a preparation in our hospital because of their analgesic, anti-inflammatory, anti-snake venom and microcirculation improvement properties and other pharmacological effects (Mei et al., 2006). Triangle grass tablets have been widely used in our hospital to treat patients with bone pain from chronic kidney disease-mineral and bone disorder (CKD-MBD). However, the effects and mechanism of triangle grass on bone metabolism in chronic kidney disease complicated with mineral and bone abnormalities are unclear.

Aim of the study: The aim of the present study was to investigate the effects of a triangle grass decoction on bone metabolism in CKD-MBD rats.

Materials and methods: CKD-MBD model rats were subjected to 5/6 nephrectomy combined with 0.5 g NaH₂PO₄/rat. Serum blood urea nitrogen (BUN), creatinine (Cr), phosphorus (P), calcium (Ca), and intact parathyroid hormone (iPTH) levels were measured with an automatic biochemical analyser. Bone mineral density was determined with a Viva CT 40 system. Bone morphogenetic protein 7(BMP-7),runt-related transcription factor 2 (Runx2) and Osterix protein levels were measured by Western blot analysis. Kidney, vertebra and thoracic aorta tissue samples were assessed by histopathology and immunohistochemistry (IHC).

Results: The degrees of membrane thickening, necrosis, swelling and cast deposition were significantly reduced in high-dose rats and Low-dose rats. Serum BUN levels were significantly reduced in the Pre-H group (P < 0.05). Hypocalcaemia and hyperphos phataemia were detected in triangle grass (P < 0.05, P < 0.05). In addition, iPTH levels were significantly increased in the Pre-H group (P < 0.05). Alkaline phosphatase (ALP)levels were significantly decreased in the Pre-H group (P < 0.05). The bone mineral density was improved in the Pre-H and Pre-L groups. BMP-7 protein levels were significantly increased in the Pre-H group (P < 0.05). The pathological changes in muscle fibres in the thoracic aorta middle membranes were significantly alleviated in rats in the Pre-H and Pre-L groups. Changes in SM22α and SMα-act in protein levels were significantly attenuated in the Pre-H group (P < 0.05, P < 0.05). Changes in Runx2 and Osterix protein levels were also significantly attenuated in the Pre-H and Pre-L groups (P < 0.05, P < 0.05).

Conclusions: Triangle grass can simultaneously ameliorate vertebral bone loss and abnormal calcification in the thoracic aorta. Triangle grass has a definite effect on bone metabolism disorder in CKD-MBD rats.

Keywords: Bone-cardiovascular axis; Cardiovascular diseases; Chronic kidney disease-mineral and bone disorder(CKD-MBD); Triangle grass (chlorophytumlaxum) decoction.