A Histopathological Study of Bovine Ganglia

Abstract

One hundred and sixty-eight ganglia from 54 cattle aged 10 days to 10 years were examined microscopically. Samples from six autonomic ganglia and one sensory ganglion were represented. Thirteen animals were clinically normal and 41 were submitted for post-mortem examination. Neuronal vacuolation, spheroid formation, lipofuscin accumulation and central chromatolysis were observed sporadically and were of varying magnitude. Neuronal vacuolation and spheroid formation were not age-related changes, while lipofuscin accumulation was more common in older animals and central chromatolysis was more common in younger cattle. Non-suppurative inflammation and neuronophagia were also common findings (23 out of 54 animals, 42.6%) in autonomic ganglia that did not contain herpesvirus DNA as determined by polymerase chain reaction. Renaut bodies, features of peripheral nerves, were most commonly noted in the vagus. None of the histopathological findings were related to any particular disease in which loss of autonomic nervous system function might be expected. Furthermore, all changes were as common in clinically normal animals as in animals with disease.

Unusual Incidence and Location of Renaut Bodies in Beagle Dogs in a Nonclinical Study

“…2,9 Supporting the idea of a link with mechanical stress, these structures have been found in the peripheral nerves of a range of species over the years, including man, elephant, dog, hamster, rat, and cattle. 4,5,7,[10][11][12][13][14] The nerves in which they were found were usually located in anatomical areas naturally susceptible to such stress and injury, for instance, the peripheral nerves of the elephant's trunk, which is used as a prehensile organ 11 or classically at the site of entrapment of median and ulnar nerves in man. 5,10 Furthermore, as in the currently acknowledged hypothesis, RBs could be successfully induced in animals undergoing mechanical stress, such as repeated mechanical trauma or compression.…”

“…18 No clinical signs linked to trauma or compression were reported in the experimental subjects, and we thus do not believe that this classical pathogenesis can explain the occurrence of RBs around the adrenal glands in our case. 13…”

“…RBs associated with mast cells in the peroneal nerve of a dog with a history of hypothyroidism and mastocytosis, showing no sign of external compression whatsoever during physical examination, 16 or the presence of these bodies in the peripheral nerves surrounding the inferior ganglion of the vagus nerve (ganglion nodosum), the cervicothoracic, cranial, and caudal mesenteric ganglia in bovines. 13 In addition, they also appear to be frequent incidental findings in experimental control Beagle dogs used in toxicity studies and were even described as part of the spontaneous background changes in a review of these dogs' spontaneous microscopic changes in the sciatic nerve. 12,17 About the Incidence and Location of RBs in This Study…”

“…18 No clinical signs linked to trauma or compression were reported in the experimental subjects, and we thus do not believe that this classical pathogenesis can explain the occurrence of RBs around the adrenal glands in our case. 13 Regarding RBs in the sciatic nerve, Weber et al also suggest that the incidence of RBs could be linked to weight, the nerves of lighter subjects examined (Marshall Beagle dogs) not being as well-protected by overlying fat and muscle tissue as the ones of heavier individuals (Harlan Beagle dogs). 9 The incidence of RBs in the sciatic nerve in the current study could thus possibly be linked to the use of this light-weighted strain of Beagle dog.…”