Intervertebral disc (IVD) degeneration is one of the primary causes of low back pain, causing disability; hence, there is no regenerative nature of the current treatments. Hyaluronic acid (HA) was reported to facilitate tissue repair and alleviate pain. Herein, we determined the therapeutic effect of HA and type II collagen (COLII) hydrogel for tissue repair targeting pain in IVD degeneration. We implanted HA/COLII hydrogel following surgically induced disc injury at coccygeal levels in the rat tail model of pain. We assessed the efficacy of the HA/COLII hydrogel in reducing pain behaviour by using the von Frey assessment, protein expression of growth-associated protein (GAP) 43 for sensory nerve innervation, and disc hydration by magnetic resonance imaging (MRI). We observed the anti-nociceptive effect of the HA/COLII hydrogel in alleviating mechanical allodynia in rats. There was an inhibition of sensory hyperinnervation indicated by the GAP43 protein in the treatment group. We revealed an increase in T1ρ mapping of MRI, indicating that the hydrogel restored disc hydration in vivo. Our findings suggest the HA/COLII hydrogel alleviates pain behaviour, inhibits hyperinnervation and promotes disc hydration for tissue repair, implying that it is a potential candidate for the treatment of degenerative disc-associated low back pain.

Vascular endothelial dysfunction is characterized by an imbalance of vasodilation and vasoconstriction, deficiency of nitric oxide (NO) bioavailability and elevated reactive oxygen species (ROS), and proinflammatory factors. This dysfunction is a key to the early pathological development of major cardiovascular diseases including hypertension, atherosclerosis, and diabetes. Therefore, modulation of the vascular endothelium is considered an important therapeutic strategy to maintain the health of the cardiovascular system. Epidemiological studies have shown that regular consumption of medicinal plants, fruits, and vegetables promotes vascular health, lowering the risk of cardiovascular diseases. This is mainly attributed to the phytochemical compounds contained in these resources. Various databases, including Google Scholar, MEDLINE, PubMed, and the Directory of Open Access Journals, were searched to identify studies demonstrating the vascular protective effects of phytochemical compounds. The literature had revealed abundant data on phytochemical compounds protecting and improving the vascular system. Of the numerous compounds reported, curcumin, resveratrol, cyanidin-3-glucoside, berberine, epigallocatechin-3-gallate, and quercetin are discussed in this review to provide recent information on their vascular protective mechanisms in vivo and in vitro. Phytochemical compounds are promising therapeutic agents for vascular dysfunction due to their antioxidative mechanisms. However, future human studies will be necessary to confirm the clinical effects of these vascular protective mechanisms.