Transplantation of the autologous submandibular gland to the lacrimal basin in rats

Purpose: In this study, we designed an animal experiment in which we transferred a part of the autologous submandibular gland without performing a microvascular anastomosis. We studied histological changes and functional effects in the transfer glands. Method: Thirty male adult Sprague-Dawley rats were divided into three groups. In each animal of the three groups, the right eye was the control eye and the left eye the experimental eye. Surgical removal of the extraorbital lacrimal gland from the control eyes was performed to create a condition simulating keratoconjunctivitis sicca. In the experimental eyes of group 1, in addition to the removal of the extraorbital lacrimal gland, a part of the autologous submandibular gland was transferred to the orbit and fixed to the intraorbital lacrimal gland. In the experimental eyes of group 2, in addition to the removal of the extraorbital lacrimal gland, an aseptic silicon rubber was transferred to the orbit and fixed to the intraorbital lacrimal gland. In the experimental eyes of group 3, there was no removal of the extraorbital lacrimal gland but instead a sham operation was performed. The histological changes and innervation pattern in the transferred submandibular gland of group 1 were observed. Tear secretion of each group was measured to study the functional effect. Results: Three months after the transplantation, the transferred submandibular glands were similar to the unoperated submandibular glands both in histology and innervation pattern. In group 1, the tear secretion in the experimental eyes was significantly greater than that of the control eyes at 2 and 3 months following transfer. In group 2, no significant difference was noted between the experimental eyes and control eyes. In group 3, the difference in tear secretion between the experimental eyes and control eyes was significant. Conclusion: The result of this study revealed that although the procedure did not involve vascular anastomosis, the transfer gland showed a normal histological appearance and good reinnervation, even 3 months after the transfer. These transferred submandibular glands continued to secrete tears. This secretion continued to increase up until the end of the experimental period.