To investigate the effect of curcumin pretreatment on renal injury and apoptosis in heat stroke rats in dry heat environment.

Fifty adult SD male rats were randomly divided into 5 groups according to the random number table, including normal temperature control group, dry heat control group, low concentration curcumin pretreatment group (curcumin 50 mg/kg), moderate concentration curcumin pretreatment group(curcumin 100 mg/kg), and high concentration curcumin pretreatment group (curcumin 200 mg/kg), 10 rats in each group. The two control groups were given a gavage of normal saline, while curcumin pretreatment group were given a gavage of curcumin with the corresponding concentration once a day for 7 consecutive days. At the 8th day, except for normal temperature control group, other group were transferred to the simulated climate cabin of dry heat environment of desert. At the time of 150th minute since the experiment began, the rats were in heat stroke states, the urine and renal tissue were harvested from the anesthetized rats. The KIM-1 level was detected by KIM-1 kit in urine. Pathological changes of renal tissues were observed by HE staining, and pathological injury score were evaluated. The apoptosis of renal cells was detected by TUNEL staining method.

In normal temperature control group, the levels of KIM-1 , renal injury pathological score, apoptosis rate of renal cell were [(100.36±5.54)ng/L], [(35.50±9.52)points], [(0.55±0.04)%], respectively. They were [(1 060.57±75.50)ng/L], [(710.67±74.60)points], [(5.53±0.48)%] in dry heat control group. The indexes levels of the low, medium, high concentration curcumin pretreatment group were [(945.73±48.07)ng/L, (701.67±64.84)points, (5.10±0.37)%], [(639.17±44.71)ng/L, (365.00±34.06)points, (2.05±0.35)%], [(592.67±34.29)ng/L, (289.00±35.08)points, (1.33±0.20)%], respectively. All the three indexes levels were significantly different among the 5 groups (F=373.70, 203.16, 289.81, all P<0.01). The KIM-1 level and renal injury pathological score of dry heat control group were significantly higher than those of normal temperature control group(t=31.04, 21.99, all P<0.01). The renal injury pathological scores and apoptosis rate of renal cell had no significant difference in the dry heat control group and the low concentration curcumin pretreatment group (t=0.22, 1.74, all P>0.05), and there were statistically significant differences between medium (t=10.33, 14.43), high (t=12.53, 19.82) concentration groups and dry heat control group (all P<0.01).

Curcumin pretreatment has protective effect on the renal injury of heat stroke rats in dry heat environment, the protective effects may partly through inhibiting apoptosis of the renal cell in such situation.