BACKGROUND: The fracture healing is impaired in osteoporosis. Piper sarmentosum is a plant, which contains potent antioxidant, naringenin that may enhance fracture healing. The present histological study aimed to determine the effects of water extract of Piper sarmentosum on the late phase of fracture healing in estrogen-deficient rats.
METHODS: Twenty four female Sprague-Dawley rats (200-250 gm) were obtained. Six rats underwent sham operation and the rest were ovariectomized. Six weeks post-ovariectomy all the rats were fractured at the mid-diaphysis of the right femur and a K-wire was inserted for internal fixation. The sham group was given vehicle (normal saline) and the ovariectomized group was randomly subdivided into three groups: (i) ovariectomized-control group supplemented with vehicle; (ii) ovariectomized+estrogen replacement therapy group treated with estrogen (100 µg/kg/day) and (iii) ovariectomized+Piper sarmentosum group treated with Piper sarmentosum water extract (125 mg/kg). Following six weeks of treatment, the rats were sacrificed and the right femora were harvested for histological assessment of fracture callus.
RESULTS: The ovariectomized-control group showed a significant delay in fracture healing compared to the sham, ovariectomized-estrogen replacement therapy and ovariectomized-Piper sarmentosum groups. The median callus score for the ovariectomized-Piper sarmentosum group was 4.50 (range, 4-5), which was significantly higher than the median callus score 3.50 (range, 3-4) for the ovariectomized-control group (P=0.019). However, there was no significant (P>0.05) difference in the callus score among the sham, ovariectomized-estrogen replacement therapy and ovariectomized-Piper sarmentosum groups groups.
CONCLUSION: Treatment with water extract of Piper sarmentosum proved beneficial in the fracture healing in estrogen-deficient rats.
KEYWORDS: Antioxidant; callus; fracture healing; histology; osteoporosis; ovariectomy
Osteoporosis which is characterized by low bone mass and microarchitectural deterioration with a consequent increase in bone fragility can be associated with various stimuli such as oxidative stress and inflammation. Postmenopausal women are more prone to osteoporosis due to reduction in estrogen which may further lead to elevation of oxidative stress and lipid accumulation which will promote osteoblasts apoptosis. Proinflammatory cytokines are elevated following estrogen deficiency. These cytokines are important determinants of osteoclasts differentiation and its bone resorption activity. The main treatment for postmenopausal osteoporosis is estrogen replacement therapy (ERT). Despite its effectiveness, ERT, however, can cause many adverse effects. Therefore, alternative treatment that is rich in antioxidant and can exert an anti-inflammatory effect can be given to replace the conventional ERT. Tualang honey is one of the best options available as it contains antioxidant as well as exerting anti-inflammatory effect which can act as a free radical scavenger, reducing the oxidative stress level as well as inhibiting proinflammatory cytokine. This will result in survival of osteoblasts, reduced osteoclastogenic activity, and consequently, reduce bone loss. Hence, Tualang honey can be used as an alternative treatment of postmenopausal osteoporosis with minimal side effects.
Labisia pumila var. alata (LP) is a phytoestrogenic herb with potential as an alternative to Estrogen Replacement Therapy (ERT) in the treatment of postmenopausal osteoporosis. LP has been reported to produce similar effects to ERT on the bone markers, but could not match ERT in terms of maintaining the bone calcium in postmenopausal osteoporosis rat model. This study aimed to examine in detail the effects of LP on the bone of postmenopausal osteoporosis rat model using bone histomorphometry.
Glabridin is an isoflavan from licorice root, which is a common component of herbal remedies used for treatment of menopausal symptoms. Past studies have shown that glabridin resulted in favorable outcome similar to 17β-estradiol (17β-E2), suggesting a possible role as an estrogen replacement therapy (ERT). This study aims to evaluate the estrogenic effect of glabridin in an in-vitro endometrial cell line -Ishikawa cells via alkaline phosphatase (ALP) assay and ER-α-SRC-1-co-activator assay. Its effect on cell proliferation was also evaluated using Thiazoyl blue tetrazolium bromide (MTT) assay. The results showed that glabridin activated the ER-α-SRC-1-co-activator complex and displayed a dose-dependent increase in estrogenic activity supporting its use as an ERT. However, glabridin also induced an increase in cell proliferation. When glabridin was treated together with 17β-E2, synergistic estrogenic effect was observed with a slight decrease in cell proliferation as compared to treatment by 17β-E2 alone. This suggest that the combination might be better suited for providing high estrogenic effects with lower incidences of endometrial cancer that is associated with 17β-E2.
Osteoporosis may cause bone fracture even under slight trauma. Osteoporotic fracture has become a major public health problem but until today, the treatments available are not satisfactory. Many pre-clinical testings on animals were done to find new agents that can be sourced from natural products and synthetic drugs for osteoporotic fracture healing. Animal models are more appropriate for fracture healing study than human subject due to several reasons including the ethical issues involved. The bones of rodents are similar to human in term of their morphological change and response to therapy. Small rodents such as rats and mice are suitable animal models for fracture healing studies as they have a similar bone remodeling system to human. To date, there is no specific guideline to carry out fracture healing studies in animal models for the evaluation of new agents. This paper highlights the protocols of various fracture and fixation methods for experimental osteoporotic fracture healing using rodent models.
Water deprivation (WD) induces changes in plasma volume and osmolality, which in turn activate several responses, including thirst, the activation of the renin-angiotensin system (RAS) and vasopressin (AVP) and oxytocin (OT) secretion. These systems seem to be influenced by oestradiol, as evidenced by the expression of its receptor in brain areas that control fluid balance. Thus, we investigated the effects of oestradiol treatment on behavioural and neuroendocrine changes of ovariectomized rats in response to WD. We observed that in response to WD, oestradiol treatment attenuated water intake, plasma osmolality and haematocrit but did not change urinary volume or osmolality. Moreover, oestradiol potentiated WD-induced AVP secretion, but did not alter the plasma OT or angiotensin II (Ang II) concentrations. Immunohistochemical data showed that oestradiol potentiated vasopressinergic neuronal activation in the lateral magnocellular PVN (PaLM) and supraoptic (SON) nuclei but did not induce further changes in Fos expression in the median preoptic nucleus (MnPO) or subfornical organ (SFO) or in oxytocinergic neuronal activation in the SON and PVN of WD rats. Regarding mRNA expression, oestradiol increased OT mRNA expression in the SON and PVN under basal conditions and after WD, but did not induce additional changes in the mRNA expression for AVP in the SON or PVN. It also did not affect the mRNA expression of RAS components in the PVN. In conclusion, our results show that oestradiol acts mainly on the vasopressinergic system in response to WD, potentiating vasopressinergic neuronal activation and AVP secretion without altering AVP mRNA expression.