Objective To explore whether pioglitazone can ameliorate radiation-induced fibrosis in rat heart.Methods A total of 46 Sprague-Dawley rats were divided into six groups (control group, pioglitazone (Pio) 10 mg·kg-1 ·d-1 group, Pio 20 mg·kg-1 ·d-1 group, 18 Gy irradiation + placebo group;18 Gy irradiation + Pio 10 mg·kg-1 ·d-1 , and 18 Gy irradiation + Pio 20 mg·kg-1 ·d-1 group).Experimental animals were exposed to radiation at the chest, then administered Pio or placebo for one month.At 3 months later, the rats were killed and their heart tissues were collected for Masson staining, Western blot analysis and real-time polymerase chain reaction assay (real-time PCR).Results Masson staining revealed significant myocardial fibrosis in rats exposed to radiation, while these changes were reduced when the rats were given Pio.Western blot analysis showed that the PPAR-γ protein expression in the heart tissue of irradiated rats were higher than in the non-irradiated group (F =12.435, P ＜ 0.05).Real-time PCR assay showed that PPAR-γ mRNA expression in the irradiation + Pio 20 mg· kg-1· d-1 group was higher than that in the Pio 20 mg· kg-1 ·d-1 group (F =2.333, P ＜ 0.05).The expression of TGF-β1 protein in the irradiation + placebo group were higher than those in the other five groups (F =17.578 ,P ＜0.05), and the CDK5 protein expression had a high level in the three irradiated groups while only the irradiation + placebo group was statistically higher than controls (F =3.651, P ＜ 0.05).Conclusions Pioglitazone may ameliorate radiation fibrosis in the rat heart through its anti-fibrotic activity, perhaps via inhibiting Cdk5-mediated PPAR-γ phosphorylation.

Pediatric solid tumors are mainly mother cell-derived tumors. It is more common in children under the age of 15 and is the main cause of non-accidental death in children. Pediatric solid tumors exist with varying epidemiology. The risk factors that have already been studied regarding to its onset are birth weight, birth order, age of parents at the time of pregnancy, parental smoking, assisted reproduction, abnormal birth, economic status, maternal education, and environmental factors. This paper reviews the current research status of epidemic factors in pediatric solid tumors.