Vascular endothelial growth factor expression (VEGF) in salivary glands of diabetic rats

Effects of 4-hexylresorcinol administration on the submandibular glands in a growing rat model

Background

4-Hexylresorcinol (4HR) is a food additive and class I histone deacetylase inhibitor. In this study, we examined the effects of 4HR administration on the submandibular gland in a growing rat model.

Methods

Four-week-old rats were used in this study. The experimental group (nine males and eight females) received 12.8 mg/kg of 4HR weekly for 12 weeks. Ten rats (five males and five females) were used as controls. The submandibular glands of rats were collected 12 weeks after the first administration of 4HR. The weight of the glands was measured. Histological analysis, immunoprecipitation-high-performance liquid chromatography (IP-HPLC), and western blotting were performed.

Results

The weights of the rat submandibular glands were higher in the experimental groups than in the control group, especially in male rats (P < 0.05). The vascular endothelial growth factor (VEGF) and testosterone in the submandibular glands were more highly expressed in 4HR-treated male rats than in untreated rats, as detected by both western blotting and immunohistochemistry. The IP-HPLC results demonstrated that the expression levels of Ki67, epidermal growth factor, and testosterone in the submandibular glands were higher in 4HR-treated male rats than in untreated rats.

Conclusions

This study demonstrated that the systemic administration of 4HR increased the weight of submandibular glands in male rats. In addition, the testosterone and VEGF expression levels in the submandibular glands increased owing to 4HR administration.

Salivary VEGF and post-extraction wound healing in type 2 diabetic immediate denture wearers

OBJECTIVE

Oral wound healing in healthy could be promoted by VEGF in saliva, and immediate denture wearing, but data in type 2 diabetes are lacking. Aims were to investigate the timeline of extraction wound healing in diabetic participants wearing immediate dentures and its correlation to salivary VEGF, as well as to examine the impact of the palatal plate on tissue VEGF during palatal wound healing in rat diabetic model.

MATERIAL AND METHODS

Healthy (42) and type 2 diabetic (36) denture wearers, candidates for teeth extractions were included. Extraction wound healing was followed via measurements of socket closure, gingival hyperaemia, pain and presence of necrosis on 3^rd, 7^th, 14^th and on 21^st-day post-extraction. Salivary VEGF was measured before and on the 3^rd and 21^st day after the extraction. In streptozotocin-induced diabetic (30) as well as non-diabetic rats (30), tissue VEGF was measured in palatal wounds healing under or without a palatal plate.

RESULTS

Type 2 diabetic prosthetic patients exhibit delayed socket closure, with pronounced hyperaemia, pain and necrosis. Salivary VEGF is increased in diabetes and positively correlates to socket closure while negatively with pain on 21^st day after the extraction. Palatal incision induced VEGF increase in non-diabetic and diabetic, but less pronounced in diabetic rats. Wound healing under the palatal plate exhibit higher tissue VEGF.

CONCLUSION

Type 2 diabetes-induced increase in salivary VEGF may mitigate diabetes-induced detrimental effects on extraction wound healing. Lack of adequate tissue VEGF response to injury may underly dysregulation of diabetic oral wound healing.

Effect of melatonin versus injectable platelet rich fibrin on critical wound healing in submandibular salivary glands of diabetic rats

Background

Diabetes mellitus (DM) has harmful effects on body organs, including submandibular salivary glands (SMGs). It impairs wound healing process that follow sialoadenectomy. Yet there is no complete cure to diabetes, the available medications tend to control the side effects of DM or manage insulin resistance. Herein we tried to investigate the possible effects of injectable platelet rich fibrin (i-PRF) and melatonin on wound healing in diabetic rats.

Material and methods

Surgical defects were created in SMGs of 30 rats after confirmation of DM induction. Then rats were randomly and equally allocated into three groups. Group I served as control group; group II received topically applied i-PRF, and group III received topically administrated melatonin. After 28 days all rats were euthanized, and SMGs were processed for histological and biochemical analysis.

Results

Both i-PRF and melatonin caused significant reduction of malondialdehyde (P < 0.0001) and caspase-3 (P < 0.001) and significant increase in vascular endothelial growth factors (P = 0.001,0.009 respectively) that increased SMGs regenerative capacity when compared to diabetic group. Melatonin showed superior results regarding the histomorphological structure of SMGs.

Conclusion

Melatonin and i-PRF can be possible candidates for improvement of wound healing events in SMGs of diabetic rats.

Pleiotropic roles of the matricellular protein Sparc in tendon maturation and ageing

Acute and chronic tendinopathies remain clinically challenging and tendons are predisposed to degeneration or injury with age. Despite the high prevalence of tendon disease in the elderly, our current understanding of the mechanisms underlying the age-dependent deterioration of tendon function remains very limited. Here, we show that Secreted protein acidic and rich in cysteine (Sparc) expression significantly decreases in healthy-aged mouse Achilles tendons. Loss of Sparc results in tendon collagen fibrillogenesis defects and Sparc−/− tendons are less able to withstand force in comparison with their respective wild type counterparts. On the cellular level, Sparc-null and healthy-aged tendon-derived cells exhibited a more contracted phenotype and an altered actin cytoskeleton. Additionally, an elevated expression of the adipogenic marker genes PPARγ and Cebpα with a concomitant increase in lipid deposits in aged and Sparc−/− tendons was observed. In summary, we propose that Sparc levels in tendons are critical for proper collagen fibril maturation and its age-related decrease, together with a change in ECM properties favors lipid accretion in tendons.