The alteration of intracellular signaling on the smooth muscle cells contraction in cat esophagitis

The effect of platelet-rich plasma on motility changes in experimental caustic esophageal burn

BACKGROUND

Besides stricture formation, diminished esophageal motility after caustic esophageal burns also plays a role in the deterioration of the clinical course. In this study, we aimed to investigate the effect of caustic burn on the esophageal contractions and the effect of platelet-rich plasma (PRP) on these changes.

METHODS

Twenty-one Wistar albino rats were divided into three groups [Sham operation (n = 8), caustic esophageal burn with NaOH (n = 6), PRP treatment after caustic burn (n = 7)]. After 3 weeks, esophagectomy was performed and contractions and EFS responses were evaluated in the organ bath.

RESULTS

KCl- and acetylcholine-induced responses were reduced in the Burn group, but increased in Sham and PRP groups (p < 0.05). EFS responses were higher in Burn group compared to the other groups. Response with L-arginine was increased in Burn group, but decreased in PRP group. There was more decrease in the contraction in Sham and PRP groups compared to the Burn group after SNP (sodium nitroprusside) incubation (p < 0.05). L-NAME (Nω-Nitro-L-arginine methyl ester) did not change the EFS responses in the Burn group, but EFS responses were decreased significantly in Sham and PRP groups (p < 0.05). EFS responses were decreased in all groups, but more in the Sham and PRP groups after Y-27632 (Rho-kinase inhibitor) incubation (p < 0.05).

CONCLUSIONS

For the first time, we demonstrated that both cholinergic and non-adrenergic non-cholinergic mechanisms are responsible for the altered motility in corrosive esophageal injury. Our results suggest that PRP treatment may be helpful in regulating the esophageal motility and decreasing altered contractions in corrosive burns. This effect may also contribute to the reduction of stricture formation, especially by reducing inappropriate contractions of the esophageal wall during the post-burn healing phase.

Cyclic AMP dependent down regulation in the relaxation of smooth muscle cells of cat esophagitis

We investigated whether the signal mechanism for relaxation may be affected by inflammation of the cat esophagus. Acute esophagitis was induced by perfusion with 0.1N HCI at a rate of 1 mL/min for 45 min over three consecutive days. We then isolated esophageal smooth muscle cells by enzymatic digestion with collagenase. We pre-contracted the isolated smooth cells with acetylcholine (ACh) (10(-5) M) and compared the agonist-induced relaxation of pre-con tracted normal cells with those of esophagitic cells. Vasoactive intestinal polypeptide (VIP) caused a dose-dependent relaxation in normal cells, and this curve was down shifted in esophagitic cells. Sodium nitroprusside (SNP) or SIN-1 (NO donor) produced dose-dependent relaxation in normal cells, which was not affected by esophagitis. 8-Br-cGMP (a cGMP ana log) also induced dose-dependent relaxation to a similar extent in both normal and esoph agitic cells. Forskolin (a cAMP activator) or db-cAMP (a cAMP analog) produced dose-dependent relaxation in normal cells, and this relaxation curve was down shifted in esoph agitic cells. Western blotting was used to determine what subtype of adenylyl cyclase was involved in the cAMP pathway. Western blot analysis of homogenates derived from esophageal smooth muscle using antibodies against adenylyl cyclase types II, III, IV and V/VI revealed the presence of type V and/or type VI only. This result suggests that relaxation via a cAMP-dependent pathway rather than a cGMP dependent-pathway is down regulated in cat acute esophagitis. This subsensitivity of the cAMP related pathway may be related to the activ ity of adenylyl cyclase V/VI.