Preganglionic Parasympathetic Denervation Rabbit Model for Innervation Studies

A Comprehensive Assessment of Tear-Film-Oriented Diagnosis (TFOD) in a Dacryoadenectomy Dry Eye Model

Tear film instability is a major cause of dry eye disease. In order to treat patients with short tear film breakup time (TBUT)-type dry eye, the development of tear film stabilizing agents is essential. However, the lack of an appropriate animal model of tear film instability has made drug development difficult. Although rabbit dry eye models have been reported in the past, there are only a few reports that focus on tear film instability. Herein, we assessed the tear film stability of a rabbit dry eye model induced by dacryoadenectomy. A clinical evaluation of the ocular surface, interferometry, and histological assessments of the cornea and conjunctiva were performed. Following the removal of the lacrimal glands, TBUT was shortened significantly, with dimple and random breakup patterns prominently observed. Furthermore, the blink rate in this model increased after dacryoadenectomy, suggesting that this model partially captured the phenotypes of human short TBUT-type dry eye and may be useful as an animal model for investigating potential drug candidates.

Local continuous glial cell derived neurotrophic factor release using osmotic pump promotes parasympathetic nerve rehabilitation in an animal model of cavernous nerve injury induced erectile dysfunction

Background

Nerve injury-related erectile dysfunction (ED) is one of the types that respond poorly to conventional ED treatments. Our previous experiments have demonstrated the paracrine of various neurotrophic factors (NTFs) by stem cells or other treatment modalities as a potential mechanism in the recovery of nerve injury-related ED. Glial cell derived neurotrophic factor (GDNF) is one of the essential NTFs for the regeneration of nerve fibers, especially for parasympathetic nerves. The aim of this study is to explore if local continuous GDNF administration is beneficial for the functional and histological recovery of nerve injury induced ED.

Methods

Eight-week-old male Sprague-Dawley rats were used for this study. Rats were randomly grouped into 5: Sham surgery (Sham), bilateral cavernous nerve injury (BCNI) and placebo treatment, BCNI and 0.1 µg/100 µL GDNF treatment (BCNI+GDNF 0.1), BCNI and 1 µg/100 µL GDNF treatment (BCNI+GDNF 1), BCNI and 10 µg/100 µL GDNF treatment (BCNI+GDNF 10). GDNF was administered using an osmotic pump technique which would deliver GDNF locally and continuously for 28 days without the need for external connections or frequent handling of animals. Recovery of sexual function, nerve fibers regeneration, and expression of neurotrophic receptors were examined and compared among groups after the treatment.

Results

Local continuous GDNF release treatment increased the average number of intromissions in the sexual behavior test and intracavernous pressure (ICP) in the erectile function test in a dose dependent manner. Osmotic pump implantation induced increased local GDNF concentration and mild inflammatory response. Gene expression of GDNF receptors in major pelvic ganglion (MPG) and nerve regeneration along the urethra were partially promoted by GDNF. These changes were associated with increased nerve fibers especially the parasympathetic nerve fibers in dorsal nerve of penis (DNP) in GDNF treated groups.

Conclusions

In conclusion, our project illustrated the promising effects of local continuous GDNF administration for the functional and histological recovery of nerve injury-induced ED.

The fifth cranial nerve in headaches

The fifth cranial nerve is the common denominator for many headaches and facial pain pathologies currently known. Projecting from the trigeminal ganglion, in a bipolar manner, it connects to the brainstem and supplies various parts of the head and face with sensory innervation. In this review, we describe the neuroanatomical structures and pathways implicated in the sensation of the trigeminal system. Furthermore, we present the current understanding of several primary headaches, painful neuropathies and their pharmacological treatments. We hope that this overview can elucidate the complex field of headache pathologies, and their link to the trigeminal nerve, to a broader field of young scientists.