Lacrimal Secretion Research Articles

Alteration in nerves and neurotransmitter stimulation of lacrimal gland secretion in the TSP-1-/- mouse model of aqueous deficiency dry eye.

The purpose of this study is to determine neural, vascular, protein secretion, and cellular signaling changes with disease progression in lacrimal glands of the thrombospondin-1−/− (TSP-1−/−) mouse model of dry eye compared to C57BL/6 wild type (WT) mice. Neural innervation was reduced in TSP-1−/− lacrimal glands compared to WT controls, whereas the number of blood vessels was increased. Intracellular Ca2+ stores and the amount of lysosomes, mitochondria and secretory granules, but not the endoplasmic reticulum, were reduced in TSP-1−/− compared to WT acini at 12 weeks of age. Ex-vivo high KCl-evoked secretion was decreased in TSP-1−/− compared to WT lacrimal gland tissue pieces. The α1D-adrenergic agonist-stimulated response was increased in TSP-1−/− at 4 and 24 weeks but decreased at 12 weeks, and the ATP and MeSATP-stimulated peak [Ca2+]i responses were decreased at 24 weeks. These changes were observed prior to appearance of mononuclear infiltrates. We conclude that in the lacrimal gland the absence of TSP-1: injures peripheral nerves; blocks efferent nerve activation, decreases protein secretion, and, alters intracellular Ca2+ stores. Through these effects the absence of TSP-1 leads to disruption of ocular surface homeostasis and development of dry eye.

Contagious keratoconjuctivitis in goats due to Branhamella (Moraxella) ovis

Incidents of contagious kerato conjuctivitis in two flocks of goats in Chalkidiki Prefecture are described. The disease was only observed in young animals approximately two years of age. The early signs were excessive lacrimation, photophobia and blepharospasm, while the bright sunlight was revealed irritating for the affected eyes. Conjunctivitis and mucopurulent secretion was also observed at the late stage of the disease. Many animals with keratitis end up totally blind. The infection of the eyes was either lateral of bilateral. Branhamella ovis was isolated in almost pure culture, from lacrimal secretion in a large number of samples (32/35). The identification was based on the organism's morphology, cultural behaviour and biochemical reactions. The microbiological examination of the samples revealed only one kind of isolate. No other organisms that could cause similar clinical findings were isolated. Therefore, it was assumed that the etiological agent of the described cases was B.ovis. It is possible that certain environmental agents such as dust, flies or bright sunlight, that were present at that time of the year because of the prolonged summer, acted as predisposing factors. Although the disease exists in our country for years, it is the first time that the pathogen agent has been isolated and identified. A successful treatment was performed at the early stage of the disease by the topical application of antibiotics.

Topical tear stimulation—a new insight for dry eye therapy

Dry eye disease is the most prevalent ocular surface disease in eye clinics. The deficiency of tears is regarded as one of the main pathogenic factors for this disease. Due to the fact that the components of tears are still far beyond our knowledge, the restoration of physiological tears remains the optimum choice for dry eye patients. However, the traditional way to stimulate tear production by systemic administration of muscarinic agonists usually encounters severe side effects. Recently, Nakamachi and colleagues reported that PACAP, a native neurotransmitter present in tear fluid, could stimulate main lacrimal gland secretion and relieve dry eye-like symptoms in PACAP knockout mice. The finding of PACAP and its underlying mechanisms suggest a new modality for dry eye treatment via targeted topical tear stimulations.

Novel tear secretion system - the effect and the mechanism of PACAP on tear secretion

Dry eye syndrome is defined as a disorder of the tear film caused by either a decreased production in tears or a disruption to the stability of the complex tear film, which causes damage to the ocular surface. It has been developed the medicine for dry eye syndrome focusing anti-inflammation or mucin secretion, however, no treatment has been developed focusing on the effect of elevation of the lacrimal secretion. We recently identified that pituitary adenylate cyclase-activating polypeptide (PACAP)-null mice develop dry eye-like symptoms such as corneal keratinization and tear reduction. PACAP receptor (PAC1-R) immunoreactivity was observed in the acinar cells of the mouse lacrimal gland. PACAP eye drop significantly stimulated tear secretion level, and the effect was suppressed by pretreatment with PAC1-R antagonist or adenylate cyclase inhibitor. PACAP eye drop on the PACAP KO mouse significantly increased the tear secretion, and continuous eye drop suppressed progression of the corneal keratinization. PACAP eye drops increase aquaporin 5 (AQP5) levels in the membrane of acinar cells in lacrimal glands. AQP5 siRNA treatment significantly attenuates PACAP-induced tear secretion. Based on these results, PACAP might be clinically useful to treat dry eye disorder.

Estrogen Modulates Corneal Nociception and Maintains Corneal Homeostasis in Rat Eye.

To evaluate the role of estrogen in corneal nociception, its influence on lacrimal secretion, and development of dry eye. Ovariectomy was performed in normal healthy female rats (OVX). Estrogen replacement was performed in a population of these rats (OVX+E). Tests for dry eye and corneal sensitivity were performed and compared with rats in proestrus (PRO) as controls. Gene expression of neuropeptides such as substance P, calcitonin gene receptor-like protein (CGRP), estrogen receptor α, TRPV1, and TRPM8 was evaluated in the cornea and trigeminal ganglion. Expression of substance P and CGRP in the cornea was also examined by immunohistochemistry. The response of the cornea to capsaicin and menthol was evaluated to identify the activity of receptors TRPV1 and TRPM8, respectively. There was a significant decrease in tear formation (4.2 ± 0.6 mm/min vs. 6.6 ± 0.42 mm/min), corneal sensitivity (2.2 ± 0.17 cm vs. 6 ± 0 cm), and increase in fluorescein staining in corneas after ovariectomy compared with controls. There was a significant decrease in gene expression of CGRP, substance P, TRPV1, and TRPM8 in the ovarioectomized cornea. A significant decrease in tear formation (3.17 ± 0.30 mm/min vs. 7.17 ± 0.87 mm/min) and eye wipe response (10.5 ± 1.99 wipes vs. 18.33 ± 1.05 wipes) after treatment with menthol and capsaicin in OVX rats was observed. Estrogen replacement significantly enhanced tear formation (4.02 ± 0.6 mm/min vs. 6.7 ± 0.80 mm/min), corneal sensitivity (2.2 ± 0.17 cm vs. 3.2 ± 0.17 cm), and response to capsaicin (10.5 ± 1.99 eye wipes vs. 24.5 ± 0.92 wipes) and menthol (3.17 ± 0.30 mm/min vs. 6.5 ± 0.22 mm/min) and increased expression of neuropeptides, TRPV1 and TRPM8. This study demonstrates the role of estrogen in corneal nociception and its deficiency as a cause of dry eye.

Botulinum neurotoxin injection for the treatment of epiphora in nasolacrimal duct obstruction

Retrospective long-term study to evaluate the efficacy of botulinum neurotoxin A (BoNT/A) therapy for epiphora due to non-surgical nasolacrimal duct obstruction. BoNT/A has been used successfully since 2000 in axillary hyperhidrosis to reduce secretory disorders. Some isolated cases of hyperlacrimation or crocodile tear syndrome have been treated on this basis. We used BoNT/A to decrease lacrimal secretion in cases of epiphora. We reviewed the qualitative and quantitative degree of improvement of epiphora after botulinum neurotoxin injections in the palpebral lobe of the lacrimal gland, carried out in an ophthalmic centre between 2009 and 2016. Epiphora was graded using a questionnaire, Munk scores and Schirmer tests before and after injections. Severity of side effects was recorded. Twenty-seven palpebral lacrimal glands of twenty patients with epiphora, mean age 65±13, were treated with BoNT/A (Botox® or Xeomin®) from April 2009 to April 2016. The epiphora was induced by persistent nasolacrimal duct stenosis after surgical treatment. No conventional medical nor surgical treatment was effective at this time. The technique of injection, dilution and dosage were specific. We re-injected 14/27 cases on an as-needed basis, 7/27 cases three times, 3/27 cases four times, and 2/27 cases (same patient both glands) five times. The Schirmer test measured a decrease of lacrimal secretion in 24/27 (89%) lacrimal glands after neurotoxin injection. Side effects were ptosis in 4 cases and transient esotropia in 2 cases. The authors describe the injection techniques, the dosage, the volume and concentration of BoNT/A. Patients with epiphora can be treated effectively with BoNT/A to reduce lacrimal secretion of the principal lacrimal gland in its palpebral portion. Ninety percent of the patients were very satisfied, with few side effects (ptosis or mild diplopia lasting from 3 days to 3 weeks). More studies are needed to delineate which types of epiphora can be treated with BoNT/A.

Central Connections of the Lacrimal Functional Unit.

To study the contribution of each eye to the reflex tear response, after unilateral and bilateral topical anesthesia. A closed-eye, modified Schirmer test was performed bilaterally in 8 normal subjects, in a controlled environment chamber set to 23°C, 45% relative humidity, and 0.08 m/s airflow. Eye drops were instilled into each eye 10 minutes before the Schirmer test. Experiments were as follows: 1) bilateral saline (control), 2) unilateral anesthesia (ipsilateral anesthetic; contralateral saline), and 3) bilateral anesthesia. There was no difference in between-eye wetting lengths in the saline control eyes (P = 0.394) or the bilaterally anesthetized eyes (P = 0.171). The wetting length was reduced in both eyes after bilateral anesthesia compared with saline controls (P = 0.001; P ≤ 0.0005). After unilateral anesthesia, the wetting length was reduced in the anesthetized eye compared with its saline control by 51.4% (P ≤ 0.0005) and compared with its fellow, unanesthetized eye (P = 0.005). The fellow eye value was also reduced compared with its saline control (P = 0.06). The wetting length was reduced by topical anesthesia, when instilled bilaterally and ipsilaterally. The latter response implies an ipsilateral, reflex sensory drive to lacrimal secretion. In the unanesthetized fellow eye, the reduction compared with its saline control was not quite significant. This implies a relative lack of central, sensory, reflex cross-innervation, although the possibility cannot entirely be ruled out. These results are relevant to the possibility of reflex lacrimal compensation from a normal fellow eye, in cases of unilateral corneal anesthesia.

The neural pathway for lacrimal gland tear secretion in New Zealand White rabbits

ObjectiveWe investigated the neural pathway for tear secretion from the lacrimal gland of New Zealand White rabbits. MethodsNine healthy adult New Zealand White rabbits were randomly divided into three experimental groups, namely, an irritant-stimulated group, a non-stimulated group, and a saline-stimulated group. Sanitized dry cotton swabs with menthol were used to wipe both of the rabbits’ eyelids in the irritant-stimulated group, and the non-stimulated group and saline- stimulated group were compared as controls. The animals in the three groups were killed 2h later and the expressions of c-Fos in the frontal cortex, hippocampus, hypothalamus, pons, and medulla oblongata of the rabbits were detected using immunofluorescence labeling. According to the distribution of c-Fos protein expression, 12 healthy adult New Zealand rabbits were similarly divided into three groups for retrograde tract tracing via pseudorabies virus (PRV) injection into the lacrimal gland. Immunofluorescence labeling was used to analyze PRV-infected neurons in the brains of rabbits after survival for 30h, 38h, and 46h. ResultsThe most c-Fos-positive immunolabeled cells were observed in the menthol-stimulated group, whereas fewer c-Fos-positive immunolabeled cells were observed in the saline-stimulated group.The non-treated group showed the least c-Fos-positive immunolabeled cells. At 30h after PRV injection, PRV-positive neurons were found only in the superior salivary nucleus of the pons (SSN). At 38h, PRV-infected neurons were observed in the lateral nucleus of the superior olive (LSO) and the medial nucleus of the superior olive (MSO). At 46h, PRV-infected neurons were found in the nucleus of the trapezoid body (Tz) and the hypothalamic paraventricular nucleus (PVN), and their distributions were dense in the LSO and MSO. ConclusionsMenthol-induced c-Fos protein expression and PRV-mediated tract tracing suggest that in New Zealand White rabbits, the neural pathway that regulates tear secretion from the lacrimal gland proceeds from the PVN to the superior olivary complex of the pons to the SSN and finally to the lacrimal gland.

Research progress on acupuncture therapy forxerophthalmia

The clinical and experimental publish literatures of the traditional acupuncture treatment for xerophthalmia were review and selected, and the acupoints and outcomes index were analyzed. The clinical studies demonstrated that acupoints around eyes, head and face were mainly coordinated with Zangfu organs and meridians; and the experimental studies showed the effect of acupuncture work through stimulation of the lacrimal gland secretion, repairing lacrimal gland structure, inhibition of apoptosis to increase the flow of tears, extending the breakup time of lacrimal film, and relieving eye related symptoms Key words: Acupuncture; Xerophthalmia; Acupoint; Review

Helicobacter pylori in lacrimal secretions.

The aim of this study was to investigate the presence of Helicobacter pylori in human lacrimal and nasal secretions. Eighty patients with complaints of dyspepsia who had undergone endoscopies and gastric antrum biopsies were included in the study. A total of five specimens, including 2 lacrimal secretion samples, 2 nasal mucosal swab samples, and 1 gastric antrum biopsy, were collected from each patient and investigated with polymerase chain reaction (PCR) methods consisting of the urease enzyme coding gene GlmM (UreC) and the H pylori-specific 16S rRNA coding gene. The Reflux Symptom Index and ophthalmologic complaints of the patients were recorded. The detected positivity rates of the H pylori 16S rRNA coding gene in gastric biopsies and nasal mucous and lacrimal secretions were 55, 11.2, and 20%, respectively. The patients were grouped as gastric-antrum-biopsy-negative (Group I [n = 36]) and -positive (Group II [n = 44). In Group II, H pylori positivity in the lacrimal and nasal mucous secretions was 36.3 and 18%, respectively. A comparison between the groups in terms of H pylori presence in nasal mucous and lacrimal secretions yielded statistically significant differences (p = 0.0001, p = 0.003). The simultaneous presence of H pylori in nasal mucous and lacrimal secretions was 13.6% in Group II. H pylori positivity in nasal mucous and lacrimal secretions had a positive moderate correlation (r = 0.40; p = 0.0003). The present study is the first report on the presence of H pylori in lacrimal secretions through nested PCR, which suggested the presence of a number of mechanisms for H pylori transmission to lacrimal secretions.

A Rare Case of IgG4-related Sclerosing Cholangitis Companied With Miculiczʼs Disease and Lymphadenitis

Introduction: IgG4-related sclerosing cholangitis (IgG4-SC) appears to be part of IgG4-related disease (IgG4-RD). We report a rare case of IgG4-SC companied with Miculicz's disease (MD) and lymphadenitis. Methods: Case Report: A 61-year male from Northeast China was admitted for pruritus and jaundice lasting for 6 months. He presented symmetric swelling of the lacrimal glands and right swelling of submandibular gland with slight dysfunction of lacrimal and salivary secretion and a 45-pound weight loss over 3 months. He had a 1-year history of left swelling of submandibular gland and lymphadenopathy. He underwent surgical excision of the swollen lymph node and left submandibular gland one year prior to hospital admission. The patient denied any history of alcohol, tomacco, or illicit drug use. Routine blood test showed the erythrocyte sedimentation rate (ESR) was markedly raised (120 mm/h). Serum biochemical data on admission were as follows: total bilirubin 241 μmol/L, alkaline phosphatase 466 U/L, alanine aminotransferase 131 U/L. Serum immunological testing displayed high levels of IgG4 (31.4 g/L) and IgG (38 g/L), and negative values of anti-SSA and anti-SSB. An ultrasound scan of the neck showed right swollen of submandibular gland (3.5 cm length × 2.5 cm width × 1.5 cm height), suggesting the possibility of chronic sialedenitis. An enhanced CT scan of abdomen revealed the common bile duct wall thickening as well as intra- and extra-hepatic bile duct dilation. The resected specimens from the left submandibular gland and lymph node one year prior to this admission were examined with HE and immunochemical stain which revealed storiform-type fibrosis, and numerous IgG4-positive plasmacytic infiltration with a ratio of IgG4/IgG-positive plasmacytes of more than 40% thus meeting the diagnostic criteria for IgG4-SC companied with MD and lymphadenitis. The patient responded well to corticosteroid therapy and remains healthy with no signs of recurrence at six-month follow-up. Results: No. Conclusion: IgG4-RD is characterized by the enlargement of involved organs, elevated levels of serum IgG4, and abundant infiltration of IgG4-positive plasmacytes in the affected organs. IgG4-SC is the hepatobiliary manifestation of IgG4-RD. Mikulicz's disease (MD) is recently recognized as IgG4-RD distinct from Sjögren's syndrome. We report a rare case of IgG4-SC companied with MD and lymphadenitis. The patient responded well to corticosteroid therapy.

Study on the influences of lacrimal secretion and tear film after interferon-alpha therapy in patients with chronic viral hepatitis

Objective To analyze the influences of lacrimal secretion and tear film after interferon-alpha therapy in patients with chronic viral hepatitis. Methods Sixty patients with chronic viral hepatitis who would accept the interferon-alpha therapy,including 30 cases of hepatitis B and 30 chronic viral hepatitis C, visited our department of ophthalmology and were enrolled in this study.All cases received eye examination,including medical history,slit lamp examination,corneal fluorescein staining(FL),tear film break-up time (BUT)and schirmer test before interferon-alpha therapy and two months after the therapy. Results In the 60 cases of chronic viral hepatitis,there were 19 dry eye cases(31.67%)and 41 non-dry eye cases(68.33%). In dry eyes group,9 of them(47.37%) were hepatitis B patients and 10 of them were hepatitis C patients(52.63%).There was significant difference in FL grade(t=-5.288,P< 0.05),BUT(t= 5.799,P< 0.05), SchirmerⅠ(t= 5.319,P< 0.05)test in hepatitis B before and two months after interferon-alpha therapy.Statistical significance had been found before and two months after therapy in FL grade(t=-9.103,P< 0.05), BUT(t= 5.682,P<0.05),SchirmerⅠtest(t= 4.592,P<0.05).The incidence of dry eye syndrome in hepatitis B patients increased from 26.70% to 53.30% two months after treated with interferon-alpha,while the incidence of dry eye syndrome in hepatitis C patients increased from 33.30% to 60.00% two months after treated with interferon-alpha. Conclusion Dry eye syndrome is one of common complications in patients with chronic viral hepatitis.Interferon-alpha therapy would influence the lacrimal secretion and damage tear film, which increased the dry symptoms in patients.We should pay attention to the side effects of interferon-alpha therapy. Key words: Hepatitis,Viral,Human; Interferon-alpha; Keratoconjunctivitis Sicca

Evaluation of the effects of serum iron levels on lacrimal gland secretion

In our study we aimed to demonstrate the relationship between the serum iron levels, and tears quality and quantity in term newborns. This study was conducted at a single institution between March 2013 and May 2013. A total of 46 newborns were prospectively enrolled. Serum iron levels were measured via the umbilical cord blood. Infants were divided into two groups according to their serum iron levels. Group A, serum iron level ≤70 μg/dL (n = 27) and Group B, serum iron level > 70 μg/dL (n = 19). The evaluation of the osmolarity was tested by using the TearLab Osmolarity System (TearLab Co, San Diego, CA, USA). The assessment of quantity was performed by using Schirmer I test. Osmolarity testing and Schirmer I test (with/without anesthesia) were performed bilaterally on the 1st day of life by an ophthalmologist. The outcomes of Schirmer I and tear osmolarity showed no statistically significant difference between right and left eyes of any infant in the groups. Moreover, there was no statistical difference between sexes in these two groups. Osmolarity was found to have a moderate negative correlation coefficient with serum iron level (r = −0.4, p < 0.01). Furthermore, there was a high positive correlation between Schirmer I with anesthesia and serum iron levels (r = 0.7, p < 0.01). We observed that the quality and quantity of the tears was lower in term newborns with lower serum iron levels than healthy newborns. These results indicate that low serum iron level could affect lacrimal gland functions.

A Histological Study on the Lacrimal Gland of the Camel (Camelus Dromedarius )

Unlike other domestic animals the dromedary camel (Camelusdromedarius) lacks the lacrimal puncta, and hence, the lacrimal secretion function seems to be confined to the washing and moistening of the anterior surface of the eyeball. This study was conducted with the aim of studying the histological structure of the lacrimal gland of the dromedary camel. The study was performed on lacrimalglandsoffifteen animals obtained from Omdurman slaughter house, Khartoum, Sudan. The results revealed that the lacrimal gland was lobulated compound tubuloacinar with clusters of serous secretory end-pieces which were lined by a simple cuboidal epithelium of pyramidal cells. The dense connective tissue capsule sent connective tissue septa which divided the gland into lobes and lobules. The intralobular ducts were lined by simple columnar epithelium, whereas the interlobular and excretory ducts were lined by stratified columnar or pseudo-stratified columnar epithelium rich in goblet cells, melanin granules and lymphatic infiltration. The lymphocytes were replaced by a well-defined ring of lymphatic nodules around the conjunctival end of the excretory duct. The watery lacrimal secretion is suggested to be helpful in washing and moistening activitiesof the anterior part of the eyeball which is important in the camel dry, hot and dusty environment. Moreover, the increased diffuse and nodular lymphaticsin the excretory ducts might be due toincreased immune response along the draining duct. Keywords: Lacrimal gland,Dromedary Camel, Histology.

Evaluation of the therapeutic use of botulinum toxin A in the periorbital region

Botulinum toxin blocks acetylcholine release at the neuromuscular junction causing paralysis that is reversed within 4 months. The toxin was well known for its lethal effect when ingested with food (botulism); however, it was found to be highly effective in various disorders, both cosmetic and noncosmetic. The therapeutic uses in ophthalmology include treatment of strabismus, spastic focal facial dystonias, induction of temporary ptosis in cases of lagophthalmos (chemotarsorrhaphy), temporary correction of dysthyroid upper eyelid retraction, suppression of lacrimal gland secretion to temporarily control gustatory lacrimation, some cases of obstructive epiphora and primary hyperlacrimation, and temporary correction of lower lid entropion. In this prospective study, we evaluate the results of using botulinum toxin A (botox) injection in some periorbital pathologies namely, focal facial dystonias, lower lid entropion, lagophthalmos, and epiphora. Fifty patients were treated with botox (20 patients with focal facial dystonias, nine with lagophthalmos, eight with lower lid entropion, and 13 with epiphora), different techniques were used according to the pre-existing pathology, and the following data were recorded: age and sex, total dose for each injection, onset and duration of effect, degree of improvement, and the occurrence of any adverse effects. The study results supported the high efficacy of botulinum toxin for treatment of blepharospasm, hemifacial spasm, lagophthalmos, lower lid entropion, and epiphora, with marked to moderate improvement in 99, 87.5, 55.5, 75, and 92.3% of patients, respectively. Few side effects occurred but they resolved spontaneously without residues. We concluded that botulinum toxin A is a safe and effective treatment with a temporary outcome that may be desirable in certain situations.

Histochemical Analysis of Glycoconjugates in the Lacrimal Gland of the Camel ( Camelusdromedarius )

The mammalian lacrimal gland secretes an aqueous solution in which different chemical substances are present, including proteins and carbohydrates. The histochemical investigations on characterization of camel lacrimal secretion are limited. This study aimed to determine the histochemical properties of the dromedary camel lacrimal gland. Glandular samples of twenty healthy adult camels of both sexes were collected at Omdurman slaughterhouse, Sudan. The camel lacrimal gland was compound with tubulo-acinar mixed secretory units, having serous and mucous cells. Best’s carmine reactionwas negative, whereas a strong positive reaction to periodic acid-Schiff's (PAS) diastase resistant was observed in most of the secretory units; the reactions to alcian blue (AB pH 2.5) and aldehyde fuchsin (AF) were strong in the glandular tubules and weak or negative in the acini. Goblet cells in the epithelium of the interlobular ducts were strongly PAS, AB pH2.5 and AF positive.Both acini and tubules showed positive reactions to acid and alkaline phosphatases especially in their apical parts. These results suggest that the predominant acini secretion was serous which contained mainly neutral mucopolysaccharides, whereas the tubules secretion was mucous thatcontained sulfated and carboxylated acid mucopolysaccharides. Moreover, the different staining properties of the camel lacrimal secretion reflect various physiological functions.

Diadenosine tetraphosphate contributes to carbachol-induced tear secretion.

The purpose of this study is to investigate if the cholinergic stimulation by carbachol on tear secretion is a direct process or if it is also mediated by purinergic mechanisms. Experiments were performed in New Zealand male rabbits. The amount of tear secretion was measured with Schirmer's test and then analyzed by a HPLC protocol in order to study the nucleotide levels. Animal eyes were instilled with carbachol (a cholinergic agonist), pirenzepine, gallamine and 4-DAMP (muscarinic antagonists), PPADS, suramin and reactive blue 2 (purinergic antagonists), and a P2Y2 receptor small interfering RNA (siRNA). Tear secretion increased with the instillation of carbachol, approximately 84 % over control values 20 min after the instillation and so did Ap4A and ATP release. When we applied carbachol in the presence of muscarinic antagonists, tear volume only increased to 4 % with atropine, 12 % in the case of pirenzepine, 3 % with gallamine, and 8 % with 4-DAMP. In the presence of carbachol and purinergic antagonists, tear secretion was increased to 12 % (all values compared to basal tear secretion). By analyzing tear secretion induced with carbachol in presence of a P2Y2 receptor siRNA, we found that tear secretion was diminished to 60 %. The inhibition of tear secretion in the presence of carbachol and purinergic antagonists or P2Y2 siRNA occurred with no apparent change in the tear amount of Ap4A. These experiments demonstrated the participation of Ap4A in lacrimal secretion process.

Establishment mice model of radiation-injured lacrimal gland and pathophysiological exploration

To establish a radiation-injured model of lacrimal gland in mice and explore its pathophysiology. Experimental research. According to the random number table, 50 healthy mice were divided into five groups:one control group (n = 10) and four experimental groups (n = 40). The experimental mice (n = 40) were exposed to different dosages of irradiation 12, 15, 18 and 21 Gy, respectively. The sham-irradiated controls (n = 10) were anesthetized in parallel with the irradiated rats but not irradiated. The mice were placed laterally and covered with a bolus material, then the X-ray irradiation was performed under general anaesthesia from above towards the mice' orbital region. The schirmer tests, Single- photon emission computed tomography/Computed tomography (SPECT/CT), HE, immunohistological, and ultrastructural examinations were conducted prior and 3 days, 7 days as well as 30 days after irradiation.Using t test to compare the differentiation of each group at the same time point. In 12 Gy group, there is no statistically significant decline in tear secretion (3 days after radiation, t = 2.137, P = 0.061;7 days after radiation, t = 1.137, P = 0.243).In 15 Gy group, Schirmer I test showed significantly reduced lachrymal secretion and the difference was statistically significant(3 days after radiation:t = 3.228, P = 0.011;7 days after radiation:t = 4.781, P = 0.001;30 days after radiation:t = 3.162, P = 0.011). Immunohistochemical findings include a significant loss in the expression of α-SMA (3 days after radiation, t = 4.395, P = 0.013; 30 days after radiation, t = 3.049, P = 0.035) , aquaporin (AQP-5) (3 days after radiation, t = 3.587, P = 0.028;30 days after radiation, t = 5.598, P = 0.005) , and an excessive expression of Tenascin-C (3 days after radiation, t = 2.964, P = 0.046;30 days after radiation, t = 4.028, P = 0.017) and CK8 (3 days after radiation, t = 5.103, P = 0.008;30 days after radiation, t = 6.178, P = 0.004) , which were statistically significant. Ultrastructural changes include a retention of secretory granules and an increase of apoptotic acinar nuclei as well as macrophage phagocytosis. Disturbance in the tracer uptake as well as reduction of the lacrimal ejection fraction was assessed under SPET/CT test and the difference was statistically significant (3 days after radiation:t = 2.796, P = 0.029;30 days after radiation:t = 2.641, P = 0.038). This radiation dosage didn't cause obvious eye complications (cataract, radiation retinopathy, etc.). At the dosages of 18 and 21 Gy, the lacrimal gland inflammation and tissue apoptosis expand obviously. The model of radiation-injured lacrimal gland was successfully constructed. Pathophysiological manifestation include the impaired structures of lacrimal gland cells and infiltration of inflammatory cells, as well as damaged function of tear secretion. These changes may prerequisites for further study on radiological protection of lacrimal glands during radiotherapy of the periorbital region for orbital tumors.

Functional presence of Na+‐K+‐2Cl‐ cotransporter in rabbit lacrimal gland ductal epithelial cells

AbstractPurpose Capability of fluid secretion of rabbit lacrimal gland duct epithelial cells was recently demonstrated by the authors using isolated duct segment model developed earlier. Inhibition of basolateral Na+‐K+‐2Cl‐ cotransporter (NKCC1) with bumetanide resulted in a complete stoppage of fluid secretion. Aim of the present work was to determine the activity and the regulation of NKCC1.Methods Experiments were performed on isolated rabbit lacrimal gland interlobular duct segments. Intracellular fluorophotometry with ammonium pulse technique was used to measure cotransporter activity. The rate of bumetanide sensitive cytosolic acidification after addition of NH4‐ can be used to quantify the activity of the cotransporter. Role of various potentially stimulatory effects were investigated.Results Unstimulated activity of NKCC1 was determined. Elevated intracellular cAMP level evoked by forskolin stimulation resulted in marked increase in NKCC1 activity. Beside increased intracellular cAMP levels, low cytosolic Cl‐ concentration and cell shrinkage evoked by hyperosmotic environment were significant determinants of increased cotransporter activity.Conclusion Our earlier results suggested the dominant role of Cl‐ dependent mechanisms in lacrimal gland ductal fluid secretion. The presented experimental work proves the substantial role of NKCC1 in basolateral Cl‐ uptake. Intracellular regulation of Cl‐ handling and luminal Cl‐ secretion needs further investigation.

The cellular mechanisms of dry eye: From pathogenesis to treatment

Dry eye is a complex disease characterized by changes in the ocular surface epithelia related to reduced quality and/or quantity of tears, inflammatory reaction, and impairment of ocular surface sensitivity. It has recently been proposed that increased tear osmolarity represents a main trigger to the altered cellular mechanisms leading to epithelial damage in dry eye. However, dry eye pathogenesis is multifactorial, with cytotoxic inflammatory mediators, altered lacrimal gland secretion and nerve function, squamous metaplasia of the conjunctival epithelium and decrease of goblet cells density, all playing a role in a detrimental loop that perpetuates and worsens damage to the corneal and conjunctival epithelia. Current topical treatments for dry eye patients include the use of lubricants and anti-inflammatory drugs. However, lubricants only improve symptoms temporarily, and chronic use of topical steroids is associated to severe ocular side effects such as cataract and glaucoma. The deeper understanding of the cellular mechanisms that are altered in dry eye is opening novel perspectives for patients and physicians, who are seeking treatments capable not only of improving symptoms but also of restoring the homeostasis of the ocular surface. In this review, we will focus on novel anti-inflammatory agents and on nerve growth factor, a neurotrophin that is altered in dry eye and has been suggested as a main player in the neuroimmune cross-talk of the ocular surface as well as in the stimulation of corneal sensitivity, epithelial proliferation and differentiation, and stimulation of mucin production by goblet cells. J. Cell. Physiol. 228: 2253-2256, 2013. © 2013 Wiley Periodicals, Inc.