Effects of Valsartan and Telmisartan on the LungTissue Histology in Sensitized Rats

The renin-angiotensin system (RAS)was potentially implicated in the pathogenesis of pulmonary disorders through its involvement in inducing pro-inflammatory mediators in the lung tissues. The present study evaluates the effects of the angiotensin receptor blockers (ARBs), telmisartan and valsartan, on the histological changes of lung tissues in sensitized rats. Twenty-fourWister female rats were randomly divided into four groups: A, negative control; B, valsartan-treated group; C, telmisartan-treated group and D, positive control. The rats in the groups B-D were sensitized and challenged with ovalbumin (OVA). Group A rats were sensitized and challenged with normal saline. Rats from groups B and C were treated with either valsartan or telmisartan (5mg/kg/day), respectively. The effects of administered ARBs on lung tissue structures were histologically evaluated. Treatment with telmisartan significantly attenuates the inflammatory and the hyper-proliferative changes in lung tissue after OVA-challenge, while valsartan did not show such effect. In conclusion, telmisartan demonstrates anti-inflammatory and anti-proliferative activities in sensitized rats, while valsartan lacks these effects.