Immunohistochemical and morphometric investigations of the influence of botulinum toxin on the submandibular gland of the rat

Abstract

Immunohistochemical methods were used to study the effects of botulinum toxin A on the concentration of acetylcholinesterase in the submandibular gland of the rat. The toxin was injected into the glands of healthy adult female Wistar rats and immunohistochemistry performed on the excised organs. Morphometric measurements were also carried out to study changes of cell morphology after local applications of botulinum toxin A. Compared with untreated glands or glands injected with saline there was a decrease of acetylcholinesterase in the glands treated with botulinum toxin. As the cholinergic pathway of the autonomic nervous systems plays an important role in eliciting secretion from the salivary glands, inhibition of secretion by local application of botulinum toxin could be considered a therapeutic option for the treatment of various diseases affecting salivary gland function.

Histological and immunohistochemical findings of the action of botulinum toxin in salivary gland: systematic review

“…Thus, it is clear that the results found by Teymoortash et al (2007), are different from those found by Ellies et al (1999), since these last authors claim to be no clear difference between the serous acini of treated and untreated groups. Teymoortash et al (2007), affirm that in the first study performed by Ellies et al (1999), morphometric evaluations were limited to the description of serous acinar cell nuclei and did not use a standard method of fixation to minimize differences in shrinkage of the tissue samples.…”

“…The use of the toxin in sialorrhea treatment was based on a publication in 1923, when Dickson and Shevsky observed that the tympanic nerve, which induces salivation, was blocked in cats infected by Clostridium botulinum (Savarese et al, 2004;Ellies et al, 1999). As a therapeutic resource, the toxin was released to patient administration just in 1989, when the FDA (Food and Drugs Administration) classified it as safe and effective drug for the treatment of movement disorders.…”

“…Currently, experimental studies of the action of botulinum toxin in salivary glands follow a pattern, in rats, and the majority refers to immunohistochemical studies. Immunohistochemical investigations were made mainly for the enzyme acetylcholinesterase (AChE) and neuronal nitric oxide synthase (nNOS) in submandibular and/or parotid glands of female rats, such as publications of Ellies et al (1999Ellies et al ( , 2000Ellies et al ( , 2003Ellies et al ( , 2006a and Ellies (2003).…”

“…The AChE activity depends on the concentration and availability of its substrate, acetylcholine, and they both vary according to the degree of cholinergic innervation of exocrine glands (Ellies et al, 1999).…”

“…Thus, besides acetylcholine transmitters, other neurotransmitters, such as NO neuromodulator may also be involved in regulating the function of the salivary gland (Ellies et al, , 2006a. Ellies et al (1999Ellies et al ( , 2000Ellies et al ( , 2003Ellies et al ( , 2006a and Ellies (2003), tested the immunoreactivity for acetylcholinesterase and neuronal nitric oxide synthase in parotid and submandibular glands of female rats and demonstrated weak immunoreactivity for these enzymes in the groups treated with botulinum toxin, becoming proportional with the increase of the time exposure to the toxin. According to histological studies in submandibular glands of female rats made by Ellies et al (1999), there is no clear difference of serous acini of glands injected with the toxin and saline in their histometric measurements, although both had a slightly higher nuclear counting than in the acini control group.…”