Vitamin D3 supplementation ameliorates ovariectomy-induced cardiac apoptotic and structural changes in adult albino rats

Vitamin D delays intervertebral disc degeneration and improves bone quality in ovariectomized rats

Known to be involved in bone-cartilage metabolism, Vitamin D (VD) may play a role in human's disc pathophysiology. Given that postmenopausal women are prone to suffer VD deficiency and intervertebral disc degeneration (IDD), this study is intended to investigate whether VD can delay IDD in ovariectomized rats by improving bone microstructure and antioxidant stress. Female Sprague-Dawley rats were randomly allocated into four groups: sham, oophorectomy (OVX)+VD deficiency (VDD), OVX, and OVX+VD supplementation (VDS). In vivo, after a 6-month intervention, imaging and pathology slice examinations showed that IDD induced by OVX was significantly alleviated in VDS and deteriorated by VDD. The expressions of aggrecan and Collagen II in intervertebral disc were reduced by OVX and VDD, and elevated by VDS. Compared with the OVX+VDD and OVX group vertebrae, OVX+VDS group vertebrae showed significantly improved endplate porosity and lumbar bone mineral density with increased percent bone volume and trabecular thickness. Furthermore, 1α,25(OH)2D3 restored the redox balance (total antioxidant capacity, ratio of oxidized glutathione/glutathione) in the disc. The cocultivation of 1α,25(OH)2D3 and nucleus pulposus cells (NPCs) was conducted to observe its potential ability to resist excessive oxidative stress damage induced by H2O2. In vitro experiments revealed that 1α,25(OH)2D3 reduced the senescence, apoptosis, and extracellular matrix degradation induced by H2O2 in NPCs. In conclusion, VDS exhibits protective effects in OVX-induced IDD, partly by regulating the redox balance and preserving the microstructure of endplate. This finding provides a new idea for the prevention and treatment of IDD.

Protective role of vitamin D3 in a rat model of hyperthyroid-induced cardiomyopathy

Background and aim

Several studies have reported the cardioprotective effect of vitamin D. Thus, this study aimed to investigate the possible cardioprotective effect of vitamin D3 in hyperthyroid-induced cardiomyopathy rat model.

Experimental procedure

Rats were divided into 3 groups: control group; hyperthyroid group, rats were administrated l-thyroxine sodium daily for 4 weeks; and hyperthyroid + vitamin D3 treated group, rats were treated with l-thyroxine sodium for 4 weeks daily, and received the vitamin D3 for the same duration. After 4 weeks, electrocardiogram (ECG) was recorded. Then, blood samples were collected for biochemical analysis. After that, the final body weight was measured, and the rats were sacrificed. Finally, the hearts were excised, weighed and were prepared for histological examination by hematoxylin and eosin, and immunohistochemistry assessment of caspase-3 and proliferating cell nuclear antigen (PCNA).

Results

Hyperthyroid rats showed significant ECG changes, increased serum levels of cardiac biomarkers, fibroblast growth factor-23 (FGF23), malondialdehyde, antioxidant enzymes, tumor necrosis factor-alpha (TNF-α) and relative heart weight compared with the control rats. Vitamin D3 coadministration with l-thyroxine resulted in significant improvement in thyroid profile, ECG parameters, significant decrease of cardiac biomarkers, FGF23, malondialdehyde, TNF-α and relative heart weight, and significant decrease of the antioxidant enzymes compared with the hyperthyroid rats. The histological study was consistent with the biochemical results. Hyperthyroid rats showed upregulation of caspase-3 and PCNA in the myocardium compared with control group. Vitamin D3 treated rats showed downregulation of caspase-3 and PCNA.

Conclusion

Vitamin D3 provides cardioprotective effects in hyperthyroid rats.

Vitamin D and advanced glycation end products and their receptors

Advanced glycation end products (AGEs) are destructive molecules in the body that, at high levels, contribute to the progression of various chronic diseases. Numerous studies have suggested a modifying effect of vitamin D on AGEs and their receptors. This study sought to summarize the effects of vitamin D on AGEs and their receptors, including receptor for AGEs (RAGE) and soluble receptor for AGEs (sRAGE). The search method initially identified 484 articles; 331 remained after duplicate removal. Thirty-five articles were screened and identified as relevant to the study topic. After critical analysis, 27 articles were included in the final analysis. Vitamin D treatment may possibly be beneficial to reduce AGE levels and to augment sRAGE levels, particularly in vitamin D-deficient situations. Treatment with this vitamin may be effective in reducing RAGE expression in some disease conditions, but might be even harmful under normal conditions. The inhibitory or stimulatory effects of vitamin D on AGE receptors are mediated by various signaling pathways, MAPK/NF-κB, ADAM10/MMP9 and AT1R. In populations with chronic diseases and concomitant hypovitaminosis D, vitamin D supplementation can be used as a strategy to ameliorate AGE-mediated complications by modifying the AGE-RAGE and sRAGE systems.