Analysis of myosin-V immunoreactive myenteric neurons from arthritic rats

The inflammatory response itself and the consequent oxidative stress are able to promote neurodegeneration. So, it is possible that enteric nervous system is affected by inflammatory diseases threatening quality of life of patients. However, gastrointestinal symptoms of arthritis are usually attributed to anti-inflammatory drugs rather than neural damage.

To confirm if the general population of myenteric neurons from the ileum and jejunum of rats is affected by arthritis.

Twenty Holtzmann rats, 58-day-old male, were used and divided in four groups: control group (C30), arthritic group (Art30), older control group (C60) and older arthritic group (Art60). At 58 days old, the animals in groups Art30 and Art60 received an injection of the complete Freund's adjuvant in order to induce arthritis. The whole-mount preparations of ileum and jejunum were processed for myosin-V immunohistochemistry. Quantitative and morphometric analyses were performed.

Groups Art30 and Art60 presented, respectively, a reduction of 2% and 6% in intestinal area when compared to their control groups. No significant differences were observed in general neuronal density among the four groups (P>0.05). Group C60 presented a reduction of 14.4% and 10.9% in mean neuronal cell body area when compared to group C30 (P<0.05), for the ileum and jejunum, respectively. The other groups had a similar mean neuronal cell body area (P>0.05).

Arthritis does not promote quantitative or morphological damages in general myenteric population. However, studies in progress have revealed some significant alterations in myenteric neurons subpopulations (nitrergic and VIP-ergic neurons).