The aim of the present study was to investigate whether
protein kinase C (PKC) was involved in the effect of mesenteric lymph duct
ligation or mesenteric lymph drainage on vascular
calcium sensitivity in
hemorrhagic shock rats. Male Wistar rats were randomly divided into
Sham,
Shock (hemorrhagic shock), Shock+Ligation (mesenteric lymph duct
ligation plus
shock) and Shock+Drainage (mesenteric lymph drainage plus
shock) groups. After being in
shock (
hypotension 40 mmHg) for 3 h, the tissue of superior mesenteric artery (SMA) was taken out for detecting the PKC expression and phospho-PKC (p-PKC) activity, and the
vascular rings of SMA were prepared and used to measure the response to gradient
calcium concentration for assaying the
calcium sensitivity, the parameters of which including tension, maximum tension (E(max)) and negative logarithm of EC(50), called the pD(2). Other
vascular rings from Shock+Ligation and Shock+Drainage groups were incubated with PKC regulator PMA or
Staurosporine before the measurement of
calcium sensitivity. The results showed that, PKC expression, p-PKC activity and
calcium sensitivity of SMA in
Shock group was significantly lower than that of
Sham group, whereas the above-mentioned indexes were significantly elevated in Shock+Ligation and Shock+Drainage groups compared with those in
Shock group. PKC agonist PMA enhanced the contractile activity of
vascular rings to gradient
calcium ions, and increased E(max) of SMA in Shock+Ligation and Shock+Drainage groups. On the contrary, PKC inhibitor
Staurosporine significantly decreased the response to gradient
calcium ions and E(max) of SMA in Shock+Ligation and Shock+Drainage groups. These results suggest that PKC plays a role in the improvement of vascular
calcium sensitivity by blockade of mesenteric lymph return in
hemorrhagic shock rats.