Abstract
Purpose: :
To compare the profiles of purinergic receptors and ectonucleosidases in the lacrimal glands of wild type (WT) and thrombospondin-1 (TSP-1) deficient mice.
Methods: :
Lacrimal gland frozen sections of WT and TSP-1 deficient 11 week old female mice were incubated with antibodies at 1:100 dilution in PBS overnight to the purinergic receptors P2X7, P2X2, P2X3, P2Y11, P2Y13 and ectonucleosidases E-NTPDase1, E-NTPDase2, E-NTPDase3 and E-NTPDase8. Following a 1 hour incubation with their secondary antibodies, slides were visualized with an Olympus inverted fluorescent microscope. A minimum of 3 animals were used for each antibody.
Results: :
In WT lacrimal gland, P2X7, P2Y11 and P2Y13 were expressed in the basal membranes of acinar cells but P2X2 and P2X3 were not detected. In TSP-1 deficient mice P2X7, P2Y11 and P2Y13 were only slightly expressed, but P2X2 and P2X3 were highly positive and found in the basolateral membranes of acinar cells. WT lacrimal gland showed strong expression of E-NTPDase1 and E-NTPDase3 in the basolateral membranes of ducts and acinar cells with less expression of E-NTPDase2 and E-NTPDase8 in these same areas. In TSP-1 deficient mice, E-NTPDase1 was detected primarily in the acinar cell lateral membranes. E-NTPDase3, ENTPDase2 and E-NTPDase8 were not detected in TSP-1 deficient lacrimal glands.
Conclusions: :
Purinergic receptor and endonucleosidase expression is reduced in lacrimal glands of TSP-1 deficient mice except for the purinergic recptors P2X2 and P2X3 which are increased. Elevated expression of P2X2/P2X3 could be correlated with cellular inflammation. The reduction or absence of ectonucleosidases in TSP-1 deficient mice may indicate their inability to degrade ATP and could change the signalling properties of lacrimal glands from these mice.
Keywords: lacrimal gland • inflammation • receptors: pharmacology/physiology