Early Phase of Type 1 Diabetes Decreases the Responsiveness of C-Fiber Nociceptors in the Temporomandibular Joint of Rats

Diabetic Corneal Neuropathy: Pathogenic Mechanisms and Therapeutic Strategies

Diabetes mellitus (DM) is a major global public health problem that can cause complications such as diabetic retinopathy, diabetic neuropathy, and diabetic nephropathy. Besides the reporting of reduction in corneal nerve density and decrease in corneal sensitivity in diabetic patients, there may be a subsequent result in delayed corneal wound healing and increased corneal infections. Despite being a potential cause of blindness, these corneal nerve changes have not gained enough attention. It has been proposed that corneal nerve changes may be an indicator for diabetic neuropathy, which can provide a window for early diagnosis and treatment. In this review, the authors aimed to give an overview of the relationship between corneal nerves and diabetic neuropathy as well as the underlying pathophysiological mechanisms of corneal nerve fiber changes caused by DM for improved prediction and prevention of diabetic neuropathy. In addition, the authors summarized current and novel therapeutic methods for delayed corneal wound healing, nerve protection and regeneration in the diabetic cornea.

Chemokines and Pain in the Trigeminal System

Chemotactic cytokines or chemokines are a large family of secreted proteins able to induce chemotaxis. Chemokines are categorized according to their primary amino acid sequence, and in particular their cysteine residues that form disulphide bonds to maintain the structure: CC, CXC, CX3C, and XC, in which X represents variable amino acids. Among their many roles, chemokines are known to be key players in pain modulation in the peripheral and central nervous systems. Thus, they are promising candidates for novel therapeutics that could replace current, often ineffective treatments. The spinal and trigeminal systems are intrinsically different beyond their anatomical location, and it has been suggested that there are also differences in their sensory mechanisms. Hence, understanding the different mechanisms involved in pain modulation for each system could aid in developing appropriate pharmacological alternatives. Here, we aim to describe the current landscape of chemokines that have been studied specifically with regard to trigeminal pain. Searching PubMed and Google Scholar, we identified 30 reports describing chemokines in animal models of trigeminal pain, and 15 reports describing chemokines involved in human pain associated with the trigeminal system. This review highlights the chemokines studied to date at different levels of the trigeminal system, their cellular localization and, where available, their role in a variety of animal pain models.

Effect of leech-centipede medicine on improving erectile function in DIED rats via PKC signalling pathway-related molecules

ETHNOPHARMACOLOGICAL RELEVANCE

Leeches (pinyin name Shui Zhi; Latin scientific name Hirudo; Hirudinea; Hirudinidae) and centipedes (pinyin name Wu Gong; Latin scientific name Scolopendridae; Chilopoda; Scolopendridae) are traditional Chinese medicines, and they belong to the family entomology. A combination of leech and centipede is used as an effective medicine to promote blood circulation and remove blood stasis in traditional Chinese medicine, and "leech-centipede" medicine has been used in many prescriptions to treat diabetic vascular disease, including diabetic erectile dysfunction (DIED). However, its specific mechanism remains unclear and requires in-depth study.

AIM OF THE STUDY

This study aimed to investigate the mechanism of "leech-centipede" medicine to improve erectile dysfunction-associated diabetes by detecting PKC pathway-related molecules.

MATERIALS AND METHODS

The active ingredients of "leech-centipede" medicine were identified using high performance liquid chromatography (HPLC). Fifty male SPF rats were injected with streptozotocin to induce the DM model. Eight weeks later, the DMED model was validated with apomorphine. The DIED rats were divided into five groups-T,P,DD,DZ, and DG-and were separately treated with tadalafil, pathway inhibitor LY333531 and low-, medium-, and high-dose "leech-centipede" medicine for 8 weeks. After treatment, the blood glucose level was measured, erectile function with apomorphine was assessed, the LOX-1, sE-selectin, sICAM-1, SOD, and MDA in serum was evaluated by enzyme-linked immunosorbent assay, and flow cytometry was performed. After the collection of penile tissue, the related protein and mRNA expression was assessed by Western blotting and PCR, and the tissue and ultrastructure were analysed by HE staining, immunohistochemistry and scanning electron microscopy.

RESULTS

After treatment, the erectile function of rats was significantly improved in the T,P,DD,DZ, and DG groups compared with that in the model group. Thus, "leech-centipede" medicine can significantly reduce the levels of LOX-1, sE-selectin, sICAM-1, EMPs and CD62P to protect vascular endothelial function and anti-platelet activation, improving DIED rat erectile function. Additionally, "leech-centipede" medicine can increase SOD expression and decrease MDA expression, reducing the possibility of oxidative stress injury in DIED rats and improving the antioxidant capacity. Moreover, "leech-centipede" therapy can dramatically reduce the protein and mRNA expression of DAG, PKCβ, NF-κB, and ICAM-1, improve vascular endothelial injury in DIED rats and inhibit abnormal platelet activation.

CONCLUSION

"leech-centipede" medicine can improve erectile dysfunction by inhibiting the expression of PKC pathway-related molecules in DIED rats and protects endothelial function and anti-platelet activation.